CVE-2026-41487

Description

Langfuse is an open source large language model engineering platform. From version 3.68.0 to before version 3.167.0, there is a role-based-access control flaw in the LLM connection update flow. An authenticated, low-privileged user of role “member” in a project could request the update of an existing LLM connection to an attacker-controlled baseUrl, causing Langfuse to reuse the stored provider secret and redirect the test request to an attacker-controlled endpoint. This could expose the plaintext provider LLM API key for that connection. The attack is only possible if a user is already part of a project and has “member” scoped access. This issue has been patched in version 3.167.0.

CVSS v3.1 Score

5.4

MEDIUM

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

EPSS — Exploit Prediction

0.0004

Probability of exploitation

0.11%

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-284 CWE-284

Affected Products

Vendor	Product	Versions
langfuse	langfuse	3.68.0 — 3.167.0

References

Advisories & Patches

https://github.com/langfuse/langfuse/commit/7527bb0d84bc0a3dc24a4b16d22ed2e46e6dddff https://github.com/langfuse/langfuse/commit/e12386f9d4368bbfff24a4ad7fd53641091605ff https://github.com/langfuse/langfuse/pull/13027 https://github.com/langfuse/langfuse/pull/13055 https://github.com/langfuse/langfuse/security/advisories/GHSA-2524-j966-gfgh

Other References

https://github.com/langfuse/langfuse/releases/tag/v3.167.0

Frequently Asked Questions

What is CVE-2026-41487? +

Langfuse is an open source large language model engineering platform. From version 3.68.0 to before version 3.167.0, there is a role-based-access control flaw in the LLM connection update flow. An authenticated, low-privileged user of role “member” in a project could request the update of an existing LLM connection to an attacker-controlled baseUrl, causing Langfuse to reuse the stored provider secret and redirect the test request to an attacker-controlled endpoint. This could expose the plaintext provider LLM API key for that connection. The attack is only possible if a user is already part of a project and has “member” scoped access. This issue has been patched in version 3.167.0. It has a CVSS v3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2026-41487? +

CVE-2026-41487 has a CVSS v3.1 score of 5.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0004, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-41487? +

CVE-2026-41487 affects products from langfuse, specifically: langfuse. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-41487? +

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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