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Vulnerability record · CVE-2026-3989 · published 12 March 2026

CVE-2026-3989: Lmsys sglang deserialization of untrusted data vulnerability

Lmsys · Sglang

SGLangs `replay_request_dump.py` contains an insecure pickle.load() without validation and proper deserialization. An attacker can take advantage of this by providing a malicious .pkl file, which will execute the attackers code on the device running the script.

7.8 CVSS 3.1 High EPSS 0.43% · top 65.3% CWE-502 · Deserialization of untrusted data
7.8CVSS 3.1 base score
0.43%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 1 tagged exploit
10 Aug 2026Last modified by NVD

Description

SGLangs `replay_request_dump.py` contains an insecure pickle.load() without validation and proper deserialization. An attacker can take advantage of this by providing a malicious .pkl file, which will execute the attackers code on the device running the script.

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/sgl-project/sglang/blob/main/scripts/playground/replay_request_dump.py Product
https://github.com/sgl-project/sglang/pull/20904 Issue TrackingPatch
https://github.com/sgl-project/sglang/releases/tag/v0.5.10 Release Notes
https://orca.security/resources/blog/sglang-llm-framework-rce-vulnerabilities/ ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-3989), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.