# CVE-2026-109227: SGLang unbounded memory allocation in video preprocessing

Source: https://junglewise.ai/threats/cve-2026-109227-sglang-through-0-5-21-contains-an-unbounded-memory-allocation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-12. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-109227 · Severity: high · CVSS 7.5 · Published 2026-10-12

SGLang is a serving framework for large language models that handles video input in chat requests. A vulnerability in video frame processing allows remote attackers to submit high-resolution videos that consume excessive memory, causing the service to crash and become unavailable. An attacker can exploit this by sending concurrent malicious requests to any SGLang deployment using Qwen-VL multimodal models.

Technologies: [SGLang](https://junglewise.ai/threats/technologies/sglang-sglang). Vendors: [SGLang](https://junglewise.ai/threats/vendors/sglang).

## Quick answers

**Is CVE-2026-109227 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-109227 being exploited in the wild.

**How severe is CVE-2026-109227?** High severity, with a CVSS score of 7.5, published 12 October 2026.

**Which products and versions are affected?** SGLang through 0.5.21.

**Is there a fix for CVE-2026-109227?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-109227 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-109227?** Check whether you run SGLang at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The preprocess_video function in qwen_vl.py decodes video frames at full source resolution before applying max_pixels limits, leading to unbounded memory allocation. Remote attackers can submit high-resolution videos to the /v1/chat/completions endpoint, and concurrent requests exhaust worker memory causing denial of service. The vulnerability requires network access to an SGLang server but no authentication.

## Affected products

- SGLang SGLang through 0.5.21

## Timeline

- 2026-10-12: disclosed

## References

- [https://pypi.org/project/sglang](https://pypi.org/project/sglang)
- [https://github.com/sgl-project/sglang](https://github.com/sgl-project/sglang)

## Related threats

- [SGLang denial of service via request ID prefix matching](https://junglewise.ai/threats/cve-2026-112266-sglang-through-0-5-22-contains-a-denial-of-service-vulnerability)
- [SGLang unbounded memory allocation in audio transcription endpoint](https://junglewise.ai/threats/cve-2026-109225-sglang-through-0-5-21-contains-an-unbounded-memory-allocation)
- [SGLang Decode worker DoS in ZeroMQ control message handling](https://junglewise.ai/threats/cve-2026-94570-sglang-contains-a-dos-vulnerability-caused-by-missing-input)
- [SGLang unauthenticated arbitrary code execution in multimodal orchestrator](https://junglewise.ai/threats/cve-2026-93088-sglang-s-multimodal-generation-runtime-is-vulnerable-to)