PT-2026-2319 · Langchain · Langchain

Lifeteam2024 · Published 2026-01-12 · Updated 2026-01-13 · CVE-2024-58340

Positive Technologies (AI Summary)

CVSS v4.0

8.7

High

Base vector

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Name of the Vulnerable Software and Affected Versions LangChain versions up to and including 0.3.1

Description LangChain versions up to and including 0.3.1 have a regular expression denial-of-service (ReDoS) issue in the MRKLOutputParser.parse() method, located in libs/langchain/langchain/agents/mrkl/output parser.py. The parser uses a regular expression that is susceptible to backtracking, which can be triggered by a crafted payload. An attacker who can control or influence the parsed text, such as through prompt injection, can cause excessive CPU usage, leading to parsing delays and a denial-of-service condition. The vulnerable method is parse().

Recommendations Update to a version of LangChain greater than 0.3.1.

Exploit

Fix

DoS

Weakness Enumeration

CWE-1333

Related Identifiers

CVE-2024-58340

PYSEC-2026-75

Affected Products

Langchain

References · 9

• 🔥 https://huntr.com/bounties/e7ece02c-d4bb-4166-8e08-6baf4f8845bb · Exploit
• https://osv.dev/vulnerability/CVE-2024-58340 · Vendor Advisory
• https://osv.dev/vulnerability/PYSEC-2026-75 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2024-58340 · Security Note
• https://github.com/langchain-ai/langchain · Note
• https://twitter.com/VulmonFeeds/status/2010901560260182119 · Twitter Post
• https://twitter.com/CVEnew/status/2010859144992157731 · Twitter Post
• https://langchain.com · Note
• https://vulncheck.com/advisories/langchain-mrkloutputparser-redos · Note