What is CVE-2023-39631?

CVE-2023-39631 is a critical-severity vulnerability in Langchain, classified under Code Injection. CVSS score: 9.8/10. Published 2023-09-01.

How severe is CVE-2023-39631?

Critical severity. CVSS v3 base score is 9.8 out of 10.

RCE in Langchain

CVE-2023-39631

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.

Vulnerability class: RCE (Remote Code Execution)

Published 2023-09-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.016 (75.0th percentile), scored 2026-10-08.

Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 75.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000

Affected products

Langchain — versions 0.0.245

Weakness classification (CWE)

CWE-94 — Code Injection

References

github.com/langchain-ai/langchain/issues/8363 (Exploit, Patch, Third Party Advisory, Issue Tracking)
github.com/pydata/numexpr/issues/442 (Exploit, Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2023-39631?: CVE-2023-39631 is a critical-severity vulnerability in Langchain, classified under Code Injection. CVSS score: 9.8/10. Published 2023-09-01.
How severe is CVE-2023-39631?: Critical severity. CVSS v3 base score is 9.8 out of 10.