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Fencer Vulns
critical 9.8

CVE-2023-39631 json

Langchain vulnerable to arbitrary code execution via the evaluate function in the numexpr library

published 2023-09-01 3 y ago modified 2026-06-17 4 mo ago also GHSA-f73w-4m7g-ch9x , PYSEC-2023-162 , PYSEC-2023-163 , EUVD-2023-0117

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 75%
public exploits
0
none known

Summary

An issue in LanChain-ai Langchain v.0.0.245 allows a remote attacker to execute arbitrary code via the evaluate function in the numexpr library.

Patch / fix

  • pypi langchain 0.0.308
  • pypi numexpr 2.8.5

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
2 y ago

Exploit prediction

1.60% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/langchain-ai/langchain/issues/8363 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/pydata/numexpr/issues/442 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi langchain
<0.0.308
0.0.308
pypi numexpr
<2.8.5
2.8.5

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.