CVE-2025-10164 lmsys sglang update_weights_from_tensor main deserialization
Remote attackers can execute arbitrary code via unsafe deserialization in the update_weights_from_tensor function of the sglang library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-10164?
CVE-2025-10164 is a medium-severity unsafe deserialization vulnerability in lmsys sglang, published on 9 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A security flaw has been discovered in lmsys sglang 0.4.6. Affected by this vulnerability is the function main of the file /update_weights_from_tensor. The manipulation of the argument serialized_named_tensors results in deserialization. The attack can be launched remotely. The exploit has been released to the public and may be exploited. The vendor was contacted early about this disclosure but did not respond in any way.
Which versions are affected by CVE-2025-10164?
3 open source packages ship an affected version, including sglang.
| Package | Affected | Fixed in |
|---|---|---|
sglang PyPI | All versions | 0.5.4 |
sglang PyPI | All versions | 0.5.4 |
sglang PyPI | All versions | 0.5.4 |
How do I fix CVE-2025-10164?
Upgrade sglang to 0.5.4 or later.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2025-10164 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-10164 exists.
Sources
Also known as GHSA-9w53-xr52-mwgj, PYSEC-2026-1919.