LangChain: MongoDBChatMessageHistory query injection can allow cross-session access

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.0 · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-106119: 0.46% estimated exploitation activity in the next 30 days; percentile 40.20 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact MongoDBChatMessageHistory did not enforce the documented string type for session identifiers at runtime. In affected applications, a structured session identifier could be interpreted as a MongoDB query condition rather than as a literal identifier. Applications are affected when they pass untrusted session identifier input to MongoDBChatMessageHistory and store multiple users’ histories in the same collection. An attacker who can invoke chat-history operations may be able to read, modify, or delete another user’s stored conversation. Applications that derive the session identifier from an authenticated, server-controlled value and enforce its type are not affected by this path. Patches The issue is fixed in @langchain/mongodb version 1.3.1. Users of affected versions should upgrade to version 1.3.1 or later. The patched version validates session identifiers at runtime and ensures they are compared as literal values in MongoDB queries. Workarounds If an immediate upgrade is…

Published by the source

8 Oct 2026, 17:52 UTC

Last modified by the source

8 Oct 2026, 18:00 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-m6rx-h84q-8r95

2. Revision 3 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-m6rx-h84q-8r95

4. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-m6rx-h84q-8r95

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# Patch Next advisory brief: CVE-2026-106119

Advisory: LangChain: MongoDBChatMessageHistory query injection can allow cross-session access
IDs: CVE-2026-106119, GHSA-m6rx-h84q-8r95
Record: https://patchnext.com/advisories/cve-2026-106119 (revision 4, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @langchain/mongodb 1.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @langchain/mongodb: affected <= 1.3.0; fixed in 1.3.1

## Suggested inspection (read-only)
- `npm ls @langchain/mongodb --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @langchain/mongodb.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m6rx-h84q-8r95 (GitHub-reviewed advisory GHSA-m6rx-h84q-8r95 lists affected ranges: npm @langchain/mongodb >=0 <=1.3.0)
- Verified: https://osv.dev/vulnerability/GHSA-m6rx-h84q-8r95 (OSV record GHSA-m6rx-h84q-8r95 lists affected ranges: npm @langchain/mongodb >=0 <1.3.1 (fixed))

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