CVE-2026-26013
Description
A flaw was found in LangChain. The ChatOpenAI.get_num_tokens_from_messages method fetches arbitrary image_url values without validation when computing token counts for vision-enabled models. This issue allows an attacker to cause Server-Side Request Forgery (SSRF) by providing malicious image URLs in user input.
Statement
To exploit this issue, an attacker needs to be able to provide a malicious image_url to a LangChain instance. However, the server responses are not returned to the attacker (blind SSRF), increasing the complexity of exploitation. Additionally, an attacker can cause the server to fetch large files, potentially resulting in a high consumption of bandwidth or CPU, causing a limited impact to availability but not a complete denial of service. Due to these reasons, this vulnerability has been rated with a low impact.
Mitigation
To mitigate this issue, manually validate that all image_url fields use the HTTP/HTTPS protocols, point to allowed public domains and do not resolve to internal IP addresses before passing messages to ChatOpenAI or any LangChain model.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.7 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | Low | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
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