CVE-2026-54027

Description

LibreChat is an enhanced ChatGPT clone that supports multiple AI providers. Prior to 0.8.4-rc1, the POST /api/files/images endpoint allows any authenticated user to upload files into any agent's tool_resources (e.g., context, execute_code) without verifying ownership or EDIT permission on the target agent. A permission check was added to the POST /api/files route in a previous patch, but the image upload route was never updated with the same check. An attacker can simply use the image endpoint instead of the file endpoint to bypass the authorization entirely. This vulnerability is fixed in 0.8.4-rc1.

CVSS v3.1 Score

6.5

MEDIUM

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

EPSS — Exploit Prediction

0.0019

Probability of exploitation

0.09%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

Affected Products

Vendor	Product	Versions
librechat	librechat	< 0.8.3

References

Advisories & Patches

https://github.com/danny-avila/LibreChat/security/advisories/GHSA-c55r-p24w-hcj5 https://github.com/danny-avila/LibreChat/security/advisories/GHSA-c55r-p24w-hcj5

Exploits

https://github.com/danny-avila/LibreChat/security/advisories/GHSA-c55r-p24w-hcj5 https://github.com/danny-avila/LibreChat/security/advisories/GHSA-c55r-p24w-hcj5

Frequently Asked Questions

What is CVE-2026-54027? +

LibreChat is an enhanced ChatGPT clone that supports multiple AI providers. Prior to 0.8.4-rc1, the POST /api/files/images endpoint allows any authenticated user to upload files into any agent's tool_resources (e.g., context, execute_code) without verifying ownership or EDIT permission on the target agent. A permission check was added to the POST /api/files route in a previous patch, but the image upload route was never updated with the same check. An attacker can simply use the image endpoint instead of the file endpoint to bypass the authorization entirely. This vulnerability is fixed in 0.8.4-rc1. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-54027? +

CVE-2026-54027 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0019, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-54027? +

CVE-2026-54027 affects products from librechat, specifically: librechat. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-54027? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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