# CVE-2026-26220: LightLLM <= 1.1.0 PD Mode Unsafe Deserialization RCE

> Remote attackers can execute arbitrary code on LightLLM servers by sending malicious pickle payloads to unauthenticated WebSocket endpoints in PD mode.

- **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:** 17 Feb 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-xxv9-73gc-96fm

## What is CVE-2026-26220?

CVE-2026-26220 is a critical unsafe deserialization vulnerability in ModelTC LightLLM, published on 17 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

LightLLM version 1.1.0 and prior contain an unauthenticated remote code execution vulnerability in PD (prefill-decode) disaggregation mode. The PD master node exposes WebSocket endpoints that receive binary frames and pass the data directly to pickle.loads() without authentication or validation. A remote attacker who can reach the PD master can send a crafted payload to achieve arbitrary code execution.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-26220?


## How do I fix CVE-2026-26220?

No fix has been published for CVE-2026-26220 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-26220 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-26220 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-26220 and fix it if it is affected.

What it is: CVE-2026-26220 is a critical unsafe deserialization vulnerability in ModelTC LightLLM, published on 17 Feb 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-2026-26220 exists.

Affected product: ModelTC LightLLM. 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-2026-26220/ (Markdown: https://insights.sbomify.com/CVE-2026-26220/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-26220
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26220
- OSV: https://osv.dev/vulnerability/CVE-2026-26220

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-26220/
Summaries are generated and may contain mistakes; the official description above is the record.