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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
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
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.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-26220 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-26220 exists.
Sources
Also known as GHSA-xxv9-73gc-96fm.