Server-Side Request Forgery (SSRF) in LangChain - CVE-2026-26013
Published: April 9, 2026
Vulnerability identifier: #VU125667
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-26013
CWE-ID: CWE-918
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: LangChain
Affected software:
LangChain
LangChain
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to server-side request forgery (ssrf) in ChatOpenAI.get_num_tokens_from_messages() when processing messages containing user-supplied image_url values for token counting. A remote attacker can supply a crafted image URL to cause a denial of service.
The issue is blind SSRF, and token counting may occur outside of model invocation such as in logging, metrics, or token budgeting flows.
How to mitigate CVE-2026-26013
Install security update from vendor's website.