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High, CVSS 8.2amended

LangChain vulnerable to unsafe deserialization of attacker-controlled objects through overly broad load() allowlists

CVE-2026-44843GHSA-pjwx-r37v-7724

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (langchain-core 1.3.3, 0.3.85), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • PyPI langchain-core

    Affected
    >= 1.0.0, <= 1.3.2<= 0.3.84
    Fixed in
    0.3.85, 1.3.3

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
8.2 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
EPSS
  • CVE-2026-44843: 0.41% estimated exploitation activity in the next 30 days; percentile 34.92 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

LangChain contains older runtime code paths that deserialize run inputs, run outputs, or other application-controlled payloads using overly broad object allowlists. These paths may call load() with allowedobjects="all". This does not enable arbitrary Python object deserialization, but it does allow any trusted LangChain-serializable object to be revived, which is broader than these runtime paths require. As a result, attacker-supplied LangChain serialized constructor dictionaries may cause trusted runtime paths to instantiate classes with untrusted constructor arguments. Applications are exposed only when all of the following are true: 1. The application accepts untrusted structured input, such as JSON, from a user or network request. 2. The application does not validate or canonicalize that input into an inert schema before invoking LangChain. 3. Attacker-controlled nested dictionaries or lists are preserved in LangChain run inputs or outputs. 4. The application uses an affected API…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-pjwx-r37v-7724

  2. Revision 1 · created ·

    Published from osv record GHSA-pjwx-r37v-7724

Agent brief

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# Patch Next advisory brief: CVE-2026-44843

Advisory: LangChain vulnerable to unsafe deserialization of attacker-controlled objects through overly broad `load()` allowlists
IDs: CVE-2026-44843, GHSA-pjwx-r37v-7724
Record: https://patchnext.com/advisories/cve-2026-44843 (revision 2, source checked 26 Oct 2026, 13:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: langchain-core 1.3.3, 0.3.85. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI langchain-core: affected >= 1.0.0, <= 1.3.2; <= 0.3.84; fixed in 0.3.85, 1.3.3

## Suggested inspection (read-only)
- `python -m pip show langchain-core`: prints the installed version. Run with the environment that serves production active.

## 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-core.
- 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://osv.dev/vulnerability/GHSA-pjwx-r37v-7724 (OSV record GHSA-pjwx-r37v-7724 lists affected ranges: PyPI langchain-core >=1.0.0 =0 <0.3.85 (fixed))
- Verified: https://github.com/advisories/GHSA-pjwx-r37v-7724 (GitHub-reviewed advisory GHSA-pjwx-r37v-7724 lists affected ranges: PyPI langchain-core >=1.0.0 =0 <=0.3.84)

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