What is CVE-2026-15969?

CVE-2026-15969 is a critical-severity vulnerability in Lmsys Sglang, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-07-30.

How severe is CVE-2026-15969?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Deserialization in Lmsys Sglang

CVE-2026-15969

SGLang contains an unauthenticated RCE in /load_lora_adapter_from_tensors via bypass of SafeUnpickler’s incomplete denylist, allowing arbitrary command execution through crafted base64-encoded pickle payloads.

Vulnerability class: Insecure Deserialization

EPSS: 0.014 (70.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Lmsys Sglang
Sglang — versions 0

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

cret@cert.org (Broken Link)
cret@cert.org (Third Party Advisory, Mitigation)

Frequently asked questions

What is CVE-2026-15969?: CVE-2026-15969 is a critical-severity vulnerability in Lmsys Sglang, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-07-30.
How severe is CVE-2026-15969?: Critical severity. CVSS v3 base score is 9.8 out of 10.