🛡️ CVE-2024-58340 — langchain

🟠 CVSS 7.5 — High ⚠️ Exploit Public CWE-1333 NVD
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

LangChain versions up to and including 0.3.1 contain a regular expression denial-of-service (ReDoS) vulnerability in the MRKLOutputParser.parse() method (libs/langchain/langchain/agents/mrkl/output_parser.py). The parser applies a backtracking-prone regular expression when extracting tool actions from model output. An attacker who can supply or influence the parsed text (for example via prompt injection in downstream applications that pass LLM output directly into MRKLOutputParser.parse()) can trigger excessive CPU consumption by providing a crafted payload, causing significant parsing delays and a denial-of-service condition.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

CVE-2024-58340 is classified as CWE-1333: Inefficient Regular Expression Complexity. A regular expression backtracks catastrophically on crafted input, consuming CPU out of proportion to input size.

Affected software

CVE-2024-58340 is recorded against 2 packages.

  • langchain (fixed in 0.3.1)
  • langchain-exa (fixed in 1.0.0a1)

Timeline and source

Published on 12 January 2026 and last revised on 14 July 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

github.com
huntr.com
www.langchain.com
www.vulncheck.com

Details

Severity HIGH
CVSS Score 7.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-1333
Public Exploit ⚠️ Yes
Source NVD
Published 2026-01-12
Updated 2026-08-11
Modified 2026-07-14
Fix URL N/A

Affected Packages

Software From version Fixed in
langchain — 0.3.1
langchain-exa — 1.0.0a1

Similar Threats

Exploit Protection

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CVE-2024-58340 carries CVSS 7.5 High rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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