Vulnerability · Published Sep 9, 2025 · Assigned by VulDB

CVE-2025-10164lmsys sglang update_weights_from_tensor main deserialization

High 7.3

In plain English

A high-severity unsafe deserialization in sglang from lmsys. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.3High

Exploit odds (30 days)0.4%top 64.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	sglang	0.5.4	GHSA-9w53-xr52-mwgj
PyPI	sglang	0.5.4	PYSEC-2026-1919

Affected products (as reported)

Vendor	Product	Versions
lmsys	sglang	0.4.6

Weakness: CWE-502, CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R

References

VDB-323203 | lmsys sglang update_weights_from_tensor main deserialization vdb-entry, technical-description
VDB-323203 | CTI Indicators (IOB, IOC, IOA) signature, permissions-required
Submit #635919 | lmsys sglang >=0.4.6 Deserialization third-party-advisory