CVE-2026-107204: Missing Auth (CVSS 9.8)

Description

LMCache through 0.5.5 contains an unauthenticated remote code execution vulnerability that allows remote attackers to execute Python code by posting scripts to the /run_script endpoint. Attackers can recover real builtins through the injected FastAPI app object, bypassing the guarded __import__, to import os and run operating system commands as the LMCache process.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0077

Probability of exploitation

0.55%

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-306 Missing Authentication

References

Other References

https://github.com/LMCache/LMCache https://github.com/LMCache/LMCache/blob/v0.5.5/lmcache/v1/internal_api_server/common/run_script_api.py#L54-L76 https://github.com/LMCache/LMCache/blob/v0.5.5/lmcache/v1/multiprocess/http_apis/common_api.py#L41-L46 https://github.com/LMCache/LMCache/issues/5510 https://www.vulncheck.com/advisories/lmcache-through-0.5.5-unauthenticated-rce-via-run-script-endpoint https://github.com/LMCache/LMCache/issues/5510

Frequently Asked Questions

What is CVE-2026-107204? +

LMCache through 0.5.5 contains an unauthenticated remote code execution vulnerability that allows remote attackers to execute Python code by posting scripts to the /run_script endpoint. Attackers can recover real builtins through the injected FastAPI app object, bypassing the guarded __import__, to import os and run operating system commands as the LMCache process. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-107204? +

CVE-2026-107204 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0077, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-107204? +

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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CVE-2026-107204