CVE-2024-58340

LangChain vulnerability

7.5 HIGHPublic exploitEPSS 0.48%

Published12 Jan 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

LangChain≤ 0.3.1

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

https://github.com/langchain-ai/langchainProduct
https://huntr.com/bounties/e7ece02c-d4bb-4166-8e08-6baf4f8845bbExploitIssue TrackingThird Party Advisory
https://www.langchain.com/Product
https://www.vulncheck.com/advisories/langchain-mrkloutputparser-redosThird Party Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2024-58340 being actively exploited?

CVE-2024-58340 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.48%.

How severe is CVE-2024-58340?

CVE-2024-58340 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.48% probability of exploitation.

Which products are affected by CVE-2024-58340?

Affected products include LangChain.

How do I fix CVE-2024-58340?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2024-58340 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.