# CVE-2026-107204: LMCache through 0.5.5 Unauthenticated RCE via /run_script Endpoint

> Remote attackers can execute arbitrary Python code via the /run_script endpoint in LMCache, leading to full system compromise.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Oct 2026
- **Updated:** 7 Oct 2026
- **Also known as:** GHSA-xgvf-x9rh-chj9

## What is CVE-2026-107204?

CVE-2026-107204 is a critical code injection vulnerability in LMCache, published on 7 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-107204?


## How do I fix CVE-2026-107204?

No fix has been published for CVE-2026-107204 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-107204 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-107204 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-107204 and fix it if it is affected.

What it is: CVE-2026-107204 is a critical code injection vulnerability in LMCache, published on 7 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-107204 exists.

Affected product: LMCache. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-107204/ (Markdown: https://insights.sbomify.com/CVE-2026-107204/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-107204
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107204
- OSV: https://osv.dev/vulnerability/CVE-2026-107204

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-107204/
Summaries are generated and may contain mistakes; the official description above is the record.