CVE-2026-109227

SGLang through 0.5.21 contains an unbounded memory allocation vulnerability in preprocess_video in qwen_vl.py that decodes frames at full source resolution before applying max_pixels limits. Remote attackers can submit high-resolution videos to /v1/chat/completions on Qwen-VL deployments, and concurrent requests exhaust worker memory causing denial of service.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 42% of CVEs (scores of 2026-10-25)

CWE

CWE-770

Published

2026-10-12

Modified

2026-10-18

Record from

the NVD, synced 2026-10-19

References

• https://github.com/sgl-project/sglang
• https://github.com/sgl-project/sglang/blob/v0.5.21/python/sglang/srt/multimodal/processors/qwen_vl.py#L267-L306
• https://github.com/sgl-project/sglang/issues/43710
• https://www.vulncheck.com/advisories/sglang-through-0.5.21-memory-exhaustion-dos-via-qwen-vl-video-preprocessing
• https://github.com/sgl-project/sglang/issues/43710

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