CVE-2024-58340

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/langchain-ai/langchain	Product
https://huntr.com/bounties/e7ece02c-d4bb-4166-8e08-6baf4f8845bb	Exploit Issue Tracking Third Party Advisory
https://www.langchain.com/	Product
https://www.vulncheck.com/advisories/langchain-mrkloutputparser-redos	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:langchain:langchain:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-01-12 23:15

Updated : 2026-01-21 17:57

NVD link : CVE-2024-58340

Mitre link : CVE-2024-58340

CVE.ORG link : CVE-2024-58340

JSON object : View

Products Affected

langchain

langchain

CWE

CWE-1333

Inefficient Regular Expression Complexity

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