How severe is CVE-2026-54027?

CVE-2026-54027 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-54027 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-54027?

CVE-2026-54027 affects Librechat. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-54027?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-54027 have an EU (EUVD) identifier?

Yes. CVE-2026-54027 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39462.

When was CVE-2026-54027 published?

CVE-2026-54027 was published on 2026-06-25 and last updated on 2026-06-26.

CVE-2026-54027

CVE-2026-54027 is a medium-severity vulnerability in Librechat with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-862.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-39462
Weakness: CWE-862
Affected product: Librechat
Published: 2026-06-25
Last modified: 2026-06-26

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.

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.
How severe is CVE-2026-54027?: CVE-2026-54027 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-54027 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-54027?: CVE-2026-54027 affects Librechat. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-54027?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-54027 have an EU (EUVD) identifier?: Yes. CVE-2026-54027 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39462.
When was CVE-2026-54027 published?: CVE-2026-54027 was published on 2026-06-25 and last updated on 2026-06-26.

References

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

Affected products (1)

cpe:2.3:a:librechat:librechat:*:*:*:*:*:*:*:*

More vulnerabilities in Librechat

CVE-2024-41704 — Critical (CVSS 9.8): LibreChat through 0.7.4-rc1 does not validate the normalized pathnames of images.
CVE-2024-41703 — Critical (CVSS 9.8): LibreChat through 0.7.4-rc1 has incorrect access control for message updates.
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CVE-2024-10361 — Critical (CVSS 9.1): An arbitrary file deletion vulnerability exists in danny-avila/librechat version v0.7.5-rc2, specifically within the…

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