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Vector Store Security — Open-Source Self-Hosted (as of 09 Jul 2026)

Grading note. A dated snapshot — accurate as of 09 Jul 2026, frozen here and kept as a permanent archive entry. Research-drafted by a pupil, graded by the 3-lens panel + sensei. Corrections applied inline; unverifiable gaps marked ⚠ PENDING (#issue) — never guessed.

How to read the labels

Practice: Never expose a self-hosted vector database to the internet without authentication — all four databases ship with auth disabled by default

⚠️ WARNING — dangerous default

Do: Treat every self-hosted Chroma, Qdrant, Weaviate, and Milvus instance as open to the world until you have explicitly enabled authentication. Before connecting any network interface, enable at minimum a static API key or token. Never bind to 0.0.0.0 before auth is configured.

For Milvus specifically: Enable authentication by setting common.security.authorizationEnabled: true in your milvus.yaml (or the equivalent environment variable MILVUS_AUTH_ENABLED: true in Docker deployments). Then immediately change the default root password — the default is literally Milvus. 🕒 verify live. Change it with the Milvus SDK before any other operation:

from pymilvus import MilvusClient
client = MilvusClient(uri="http://localhost:19530", token="root:Milvus")
client.update_password(user_name="root", old_password="Milvus", new_password="<your-strong-password>")

For Weaviate specifically: Do not copy tutorial Docker Compose files that include AUTHENTICATION_ANONYMOUS_ACCESS_ENABLED: 'true' into production. In production, that variable must be 'false' (or removed entirely, since false is the default). Copy-pasted tutorial compose files are the most common way Weaviate is deployed with auth disabled.

Why: All four databases described here start without any login requirement. Anyone who can reach the port — including anyone on the same server, the same Docker network, or (if you expose a port) the entire internet — can read, write, delete, or poison every vector and document stored in the database. The data fed into a RAG pipeline is usually sensitive: customer conversations, internal documents, PII. An open database hands all of that to the first person who runs a port scan.

Evidence of real-world harm: A survey conducted in April 2025 found 1,170 internet-accessible Chroma instances, of which 406 (roughly one-third) exposed data including PII from Canva Creators and customer support chat logs from e-commerce companies. Chroma’s own documentation states: “By default, Chroma does not require authentication. You must enable it manually.”

The same unauthenticated-by-default posture applies to the others:

Sources:

Confidence: ✅ independently-corroborated (UpGuard independent research + four separate vendor doc confirmations of unauthenticated defaults)

Practice: Enable TLS on all client connections; use a reverse proxy if the database’s native TLS has performance or certificate-management drawbacks

Do: Encrypt all traffic between your application and the vector database using TLS 1.2 or 1.3. For Qdrant, set QDRANT__SERVICE__ENABLE_TLS: "true" with cert/key paths. For Milvus, set tlsEnabled: true in milvus.yaml and supply server.pem/server.key/ca.pem. For Weaviate, configure TLS at the reverse proxy layer (Weaviate’s own TLS docs are sparse). For Chroma, prefer a reverse proxy (nginx, Caddy, Envoy) for TLS termination rather than Chroma’s built-in uvicorn SSL, which carries a performance penalty.

Why: Without TLS, an API key sent in a header travels across the network as plain text. Anyone who can observe traffic on the same subnet — another container, another VM on the same hypervisor, anyone on a shared network — can capture the key and use it to authenticate. Qdrant’s documentation states that when using API key authentication, TLS should also be enabled to protect the key from network sniffing and man-in-the-middle attacks.

Caveat: Chroma’s cookbook notes that using certificates directly within Chroma’s uvicorn server has a measurable performance impact and that self-signed certificates are not recommended for production. The practical recommendation is TLS termination at nginx or Caddy in front of Chroma. For Qdrant, TLS can alternatively be terminated at a reverse proxy rather than inside Qdrant itself.

Sources:

Confidence: 📄 vendor-documented (multiple vendor sources; SSL-proxy pattern corroborated by independent ChromaDB cookbook)

Practice: Use per-service scoped credentials — never give every application component a single admin key

Do: Issue separate, minimally-scoped credentials to each service that touches the vector database. For Qdrant (v1.9+), enable JWT RBAC (QDRANT__SERVICE__JWT_RBAC: "true") and mint JWT tokens scoped to specific collections and operations (read-only r or read-write rw). Set a separate read-only key (QDRANT__SERVICE__READ_ONLY_API_KEY) for query-serving services. For Milvus, create named users and roles with COLL_RO/COLL_RW/DB_ADMIN privilege groups rather than sharing the root account. For Weaviate (v1.29+, GA Feb 2025; 🕒 current stable is 1.38 — 1.29 is no longer in the supported version window), define custom RBAC roles through AUTHORIZATION_RBAC_ENABLED: 'true' and assign them per-user via the management API.

Why: A single admin key shared across your ingestion pipeline, your RAG retrieval service, and your monitoring dashboard means one leaked credential compromises everything. Scoped credentials limit blast radius: a compromised read-only key can expose data but cannot corrupt or delete it.

Caveat: Qdrant’s JWT RBAC requires version 1.9 or later — verify your running version. Milvus RBAC configuration syntax differs slightly across v2.4.x, v2.5.x, and v2.6.x branches; check the version-specific docs. Weaviate’s built-in Admin list and RBAC cannot be used simultaneously — pick one scheme and stick to it.

Sources:

Confidence: 📄 vendor-documented

Practice: Isolate vector database ports to internal Docker networks; never publish database ports directly to the host without a firewall rule

Do: In Docker Compose, place your vector database container on an internal network shared only with the services that need to reach it. Do not use ports: mappings that bind to 0.0.0.0 (the host’s all-interfaces address). If you must expose a port for an admin UI, bind it to 127.0.0.1 only. Do not use --network=host in production.

Example (Qdrant in Compose):

services:
  qdrant:
    image: qdrant/qdrant
    networks:
      - internal
    # No "ports:" block — the app service reaches qdrant via the internal network name

  app:
    networks:
      - internal
      - external   # app needs internet access for embedding API calls

networks:
  internal:
    driver: bridge
    internal: true   # prevents external ingress AND egress for containers on this network only
  external:
    driver: bridge

⚠️ WARNING: Setting internal: true on a Docker network also blocks outbound internet calls from all containers on that network — including your vector database container attempting to pull model weights or reach an external embedding API. Use a separate network for components that need internet access (see external network in the example above). Do not put your app service on the internal network alone if it needs to reach external APIs.

Why: Docker’s default bridge network exposes all container ports to other containers on that bridge. If you also add a ports: - "6333:6333" mapping, the port becomes reachable from the host machine and potentially from the internet if no firewall rule blocks it. Many developers add that mapping “just to test something” and forget to remove it. Using internal: true on the vector DB’s network means no outside entity can reach it directly through Docker networking.

Caveat: Using --network=host (often copied from quick-start guides) removes Docker network isolation entirely. Quick-start guides for all four databases frequently include exposed ports for convenience — treat these as development-only configurations.

Sources:

Confidence: ✅ independently-corroborated (vendor network-isolation docs + independent UpGuard research documenting real-world exposure)

Practice: Patch Milvus immediately if running any version below 2.4.24, 2.5.21, or 2.6.5 — CVE-2025-64513 allows full unauthenticated admin access

⚠️ WARNING — active CVE, CVSS 9.3 CRITICAL

Do: Check your Milvus version. In a Docker deployment: docker inspect <container-name> | grep -i version or curl http://localhost:9091/api/v1/health. If your version falls below 2.4.24, 2.5.21, or 2.6.5, upgrade immediately. As of Jul 2026, Milvus 2.6.x is at v2.6.19 (released Jul 1 2026) — upgrade to the latest patch in your branch, not just the minimum fixed version. 🕒 verify live for the current latest.

If you cannot upgrade immediately, strip all sourceID headers from inbound requests at your load balancer or API gateway before they reach the Milvus Proxy. If you do not have a load balancer, the only safe option is to upgrade or take the service offline — the bypass occurs before authentication, so authentication being enabled does not protect you.

Why: CVE-2025-64513, published November 2025 (CVSS 9.3 Critical), is an authentication bypass in the Milvus Proxy. The Proxy base64-decodes an incoming sourceID header and compares it against an internal constant value. Any unauthenticated attacker who sends a request with that header value forged is treated as a trusted internal member — bypassing all authentication and RBAC controls, regardless of whether authentication is enabled. The attacker gains full admin access: read, modify, delete vectors, and manage databases and collections.

The true affected range is broad: the GHSA advisory lists all versions from approximately 0.10.4 onward as affected, with patches at 2.4.24, 2.5.21, and 2.6.5. The advisory does not address Milvus 3.0.x (beta as of May 2026) — neither safe nor affected can be concluded from the advisory for 3.0.x. 🕒 verify live before treating 3.0.x as a safe migration path.

Sources:

Confidence: ✅ independently-corroborated (GitHub Advisory Database + NVD + independent security news coverage)

Practice: Do not run ChromaDB’s Python FastAPI server accessible to any untrusted network — CVE-2026-45829 (ChromaToast) is pre-auth RCE, CVSS 10.0, and has no confirmed patch as of 09 Jul 2026

⚠️ WARNING — unpatched critical RCE, CVSS 10.0 CRITICAL

Do: If you run ChromaDB’s Python FastAPI server (any version from 1.0.0 onward), restrict network access to the ChromaDB port to a strictly trusted internal network immediately. Do not expose the port to the public internet under any circumstances, and do not treat authentication as a compensating control — the RCE fires before auth is checked.

NVD (fetched 09 Jul 2026) lists the affected range as all versions 1.0.0 and later, with no upper bound and no confirmed patched version. Multiple independent sources (BleepingComputer, Hadrian, SecurityWeek) confirm that ChromaDB 1.5.9 (released May 5 2026) remains vulnerable. 🕒 Check the NVD record and ChromaDB’s GitHub releases regularly for patch availability.

Consider migrating to the Rust-based ChromaDB server implementation, which is stated to be unaffected. Verify this in the official security advisory before relying on it.

Why: CVE-2026-45829 (“ChromaToast”), disclosed May 2026 by the HiddenLayer security team, is an unauthenticated remote code execution vulnerability in ChromaDB’s Python FastAPI server. An attacker sends a specially crafted HTTP POST to the collection creation endpoint that references a malicious HuggingFace model with trust_remote_code=true. ChromaDB loads the model code before it checks who sent the request, so the attacker’s code runs on the server before authentication ever happens. The attacker gets a shell, can exfiltrate API keys and environment variables, and has full control of the host process. The HiddenLayer team found approximately 73% of internet-exposed ChromaDB instances were running vulnerable versions.

The ChromaDB development team had not responded to multiple disclosure attempts as of the publication date. The vulnerability was first reported in November 2025 and re-reported in February 2026.

Sources:

Confidence: ✅ independently-corroborated (SecurityWeek + Cloud Security Alliance + The Cyber Express + NVD — multiple independent publishers; NVD confirms CVSS 10.0 and open-ended affected range)

Practice: Upgrade Weaviate to 1.33.4+ (CVE-2025-67818) and 1.38.0+ (CVE-2026-59093) to close a path-traversal and a privilege-escalation hole

⚠️ WARNING — two separate CVEs requiring version upgrades

Do: Check your Weaviate version. In a typical Docker deployment: docker inspect <container-name> | grep -i image or inspect the image tag. If you are on Weaviate below 1.33.4, upgrade to close CVE-2025-67818 (path traversal via backup restore). If you are below 1.38.0, also upgrade to close CVE-2026-59093 (privilege escalation via unchecked RBAC role assignment). As of Jul 2026, the currently supported Weaviate versions are 1.36, 1.37, and 1.38 — anyone on 1.33.x has already left the support window; upgrade to 1.38.x.

If you cannot upgrade immediately: for CVE-2025-67818, disable backup modules by removing all backup* entries from the enabled_modules flag. For CVE-2025-67819 (companion path-traversal in Shard Movement), set REPLICA_MOVEMENT_ENABLED: false.

Why:

Sources:

Confidence: ✅ independently-corroborated (vendor security release + NVD + GitHub Advisory for both CVEs; note CVSS score disagreement on CVE-2025-67818)

Practice: For multi-tenant RAG, enforce tenant isolation at the database layer using per-tenant collections/namespaces — never rely on application-layer filtering alone

Do: Choose one of two architectural patterns and enforce it consistently:

In both patterns, enforcement must happen at the database or gateway layer. LLMs are non-deterministic and susceptible to prompt injection; system-prompt “stay in your lane” instructions are not a security control.

Why: If two customers’ documents are stored in the same vector database without isolation, a retrieval query from Customer A could pull up Customer B’s documents — a data breach. A single code path that skips the tenant filter is a breach. The Silo pattern avoids filter-omission bugs but scales poorly — 500 tenants means 500 HNSW indexes, each consuming memory even when idle. Neither pattern prevents a malicious document from one tenant poisoning the embedding space in a shared pool.

Caveat: The Pool pattern with metadata filtering requires absolute discipline in application logic to ensure cross-tenant queries are impossible. Modern enterprise architectures often favor Pool + fine-grained access control enforced at the database engine level (e.g., via JWT-driven backend roles in OpenSearch), not purely at the application layer.

Sources:

Confidence: ✅ independently-corroborated (independent architectural guide + Qdrant vendor docs)

Practice: Self-hosted vector databases provide no built-in encryption at rest — apply OS-level or volume-level encryption for sensitive data

Do: Because none of the four databases (Chroma, Qdrant, Weaviate, Milvus) provide application-level encryption at rest in their open-source self-hosted form, protect data at the infrastructure layer: use LUKS-encrypted volumes on Linux, encrypted EBS volumes on AWS, or encrypted persistent disks on GCP/Azure for the directories where the database stores its index files.

Why: Encryption at rest protects data if someone physically removes the disk or gains access to a backup snapshot. Without it, anyone with filesystem access to the server can copy the raw index files and read the data offline without going through the database’s authentication layer.

Caveat: This practice is documented by absence of a feature rather than a positive claim, so treat it as thin — verify each project’s current release notes before assuming no change. The claim that Chroma’s DuckDB layer has no encryption roadmap comes from a single community GitHub discussion; treat as thin specifically for Chroma’s timeline. For Weaviate Cloud and Chroma Cloud managed services, encryption at rest is provided by the managed offering — this practice applies only to self-hosted deployments.

Sources:

Confidence: thin — verified that none of these databases document built-in at-rest encryption for self-hosted use; verify each project’s current release notes before assuming no change

Practice: Subscribe to each project’s security advisories and maintain a patching schedule — all four databases have issued critical CVEs within the past 12 months

Do: Set up GitHub watch notifications (“Watch → Custom → Security alerts only”) on these repositories:

All four have had high-severity or critical issues in the 8-month window between November 2025 and July 2026. These are production data-layer components for AI pipelines that handle sensitive documents; they must be included in your standard vulnerability management program.

Why: Vector databases are new enough that security review is still catching up with their feature surface. The same properties that make them useful for AI — they load model code, process complex embeddings, handle multi-tenant queries — also create new attack surfaces. Four separate critical-to-high CVEs in under a year across the major open-source options signals that this software class requires active patching attention.

Caveat: 🕒 Release cadences vary: Milvus and Weaviate release frequently (multiple times per month in 2026); Chroma’s 1.5.9 release appeared in May 2026 but the ChromaToast vulnerability remained unpatched. A monitoring subscription only helps if you act on alerts within a documented SLA (e.g., “critical CVEs patched within 7 days”).

Sources:

Confidence: ✅ independently-corroborated (four independent sources documenting separate CVEs across four vendors)

Held pending fixes (not publish-ready)

CHANGELOG (grading → this entry)

  1. Beginner KILL: Practice 1 Milvus — added explicit auth enablement steps (MILVUS_AUTH_ENABLED: true, SDK password-change snippet). Previously the danger was named but the fix was not shown.

  2. Beginner KILL: Practice 1 Weaviate — stated explicitly that AUTHENTICATION_ANONYMOUS_ACCESS_ENABLED must be set to 'false' or removed. Previously the dangerous setting was identified but the correct production value was not given.

  3. Timekeeper KILL: CVE-2026-45829 ChromaToast — changed “1.0.0–1.5.8” (closed range) to “all versions 1.0.0 and later with no confirmed patched version” per NVD record fetched Jul 2026. 1.5.9 confirmed vulnerable by BleepingComputer and Hadrian.

  4. Timekeeper KILL: CVE-2026-45829 — added explicit CVSS 10.0 CRITICAL score (NVD confirmed). Previously stated only “CVSS Critical” without a number.

  5. Timekeeper FIX: CVE-2026-45829 — sharpened patch-status caveat: “1.5.9 confirmed still vulnerable as of 09 Jul 2026” instead of “verify current patch status.”

  6. Skeptic KILL: Practice 8 (multi-tenancy) — removed “95% of benign queries triggered cross-tenant leakage” statistic. Not present on truto.one (the cited source) or any other fetched source. Fabricated stat.

  7. Skeptic FIX: CVE-2026-59093 CVSS — updated from “0 (pending)” to “8.8 HIGH (CVSS 3.1) / 8.7 HIGH (CVSS 4.0) per NVD” (published Jul 2, 2026). Replaced low-authority akaoma.com tracker with NVD as primary cite.

  8. Timekeeper FIX: CVE-2025-64513 Milvus — added note that GHSA advisory does not address 3.0.x (neither safe nor affected confirmed). Added mention of current latest v2.6.19 (released Jul 1 2026); directed readers to upgrade to latest patch, not just the minimum fixed version.

  9. Timekeeper FIX: CVE-2025-67818 Weaviate — flagged CVSS score disagreement (CISA-ADP 7.2 vs GitHub Advisory 8.7 vs Weaviate blog “Medium”; NVD final score not assigned). Added 🕒 verify live.

  10. Timekeeper FIX: Weaviate upgrade path — added note that 1.33.x is outside the current supported version window (1.36/1.37/1.38 supported); directed readers to 1.38.x.

  11. Timekeeper FIX: Weaviate RBAC note — added “1.29 is no longer in the supported version window; current stable is 1.38.”

  12. Skeptic FIX: Practice 2 TLS — removed quotation marks around Qdrant TLS warning (not verbatim on cited page); rephrased as paraphrase.

  13. Skeptic FLAG: CVE-2025-64513 Milvus affected range — added note that the true lower bound per the advisory is approximately ≥0.10.4; the “2.4.0” threshold in the advisory reflects the minimum supported Milvus series, not the actual first-affected version.

  14. Beginner KILL: Practice 4 Docker — added ⚠️ WARNING that internal: true also blocks outbound internet calls; added two-network compose example to show how to separate the vector DB’s internal network from the app’s external network.

  15. Beginner KILL: Practice 5 Milvus CVE — added docker inspect and health-check API command to check running Milvus version. Added explicit fallback for users without a load balancer: “upgrade or take the service offline.”

  16. Timekeeper FIX: Added 🕒 verify live to Milvus default root password “Milvus” — vendor can change security defaults without a major release.

  17. Beginner FLAG: Practice 7 Weaviate — clarified version-check method for Docker deployments (docker inspect rather than weaviate --version which won’t work in containers).

  18. Timekeeper FLAG: Held-pending-3 (ChromaDB 1.5.9 patch status) promoted to confirmed finding in the main practice text (KILL applied above).

  19. Link-check gate: 8 non-200 URLs unlinked to plain text (4 × milvus.io, 4 × nvd.nist.gov — all return 403/bot-protection to curl; all confirmed live via WebFetch Jul 2026). Citations retained as plain text with URLs.