Auth bypass in Lmcache
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/LMCache/LMCache/issues/5510 (issue-tracking)
- github.com/LMCache/LMCache (product)
- github.com/LMCache/LMCache/blob/v0.5.5/lmcache/v1/internal_api_server/common/ru… (technical-description)
- github.com/LMCache/LMCache/blob/v0.5.5/lmcache/v1/multiprocess/http_apis/common… (technical-description)
- www.vulncheck.com/advisories/lmcache-through-0.5.5-unauthenticated-rce-via-run-… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-107204?
- CVE-2026-107204 is a critical-severity vulnerability in Lmcache, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-10-07.
- How severe is CVE-2026-107204?
- Critical severity. CVSS v3 base score is 9.8 out of 10.