CVE-2026-110809
Deferred Deferred - Pending Action

Session Cleanup DoS in SGLang

Publication date: 2026-10-15

Last updated on: 2026-10-15

Assigner: VulDB

Description
A security vulnerability has been detected in sgl-project SGLang up to 0.5.19. Affected by this issue is the function Session.create_req of the file python/sglang/srt/session/session_controller.py of the component Session Cleanup. Such manipulation leads to denial of service. The attack may be performed from remote. The exploit has been disclosed publicly and may be used. The pull request to fix this issue awaits acceptance.

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Meta Information

Published
2026-10-15
Last Modified
2026-10-15
Generated
2026-10-19
AI Q&A
2026-10-15
EPSS Evaluated
2026-10-18
NVD
CVE-2026-110809
EUVD
EUVD-2026-101799

Affected Vendors & Products

Showing 20 associated CPEs
Vendor Product Version / Range
sgl-project SGLang 0.5.0
sgl-project SGLang 0.5.1
sgl-project SGLang 0.5.2
sgl-project SGLang 0.5.3
sgl-project SGLang 0.5.4
sgl-project SGLang 0.5.5
sgl-project SGLang 0.5.6
sgl-project SGLang 0.5.7
sgl-project SGLang 0.5.8
sgl-project SGLang 0.5.9
sgl-project SGLang 0.5.10
sgl-project SGLang 0.5.11
sgl-project SGLang 0.5.12
sgl-project SGLang 0.5.13
sgl-project SGLang 0.5.14
sgl-project SGLang 0.5.15
sgl-project SGLang 0.5.16
sgl-project SGLang 0.5.17
sgl-project SGLang 0.5.18
sgl-project SGLang 0.5.19

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-404 The product does not release or incorrectly releases a resource before it is made available for re-use.

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Executive Summary

This vulnerability is a denial of service issue in SGLang up to version 0.5.19. It occurs in the Session.create_req function of session_controller.py where the code attempts to delete entries from a dictionary while iterating over it. This violates Python's dictionary iteration rules and causes a RuntimeError, leading to a server crash via SIGQUIT signal. The issue is triggered when a session is executed with replace: true and no request ID specified.

Detection Guidance

Monitor SGLang server logs for RuntimeError messages like 'dictionary changed size during iteration' or SIGQUIT signals. Check server health endpoints such as /health for unresponsiveness. Use the provided PoC script to simulate the attack and observe server crashes.

Impact Analysis

This vulnerability allows remote attackers to crash the SGLang server by sending a specially crafted request. When exploited, the server becomes unreachable and health checks fail, causing downtime for services relying on SGLang. The attack requires only network access and does not need authentication.

Compliance Impact

This vulnerability causes a denial of service by crashing the SGLang server, making it unreachable. For GDPR, this could impact availability of services processing personal data, potentially violating Article 32 requirements for resilience. For HIPAA, service unavailability may disrupt access to protected health information, risking compliance with Security Rule standards for access controls and contingency planning.

Mitigation Strategies

Apply the patch from pull request #41483 to fix the session cleanup logic. Avoid using the 'replace: true' parameter without a valid 'rid' in session requests. Monitor for server crashes and update to the latest SGLang version once the fix is merged.

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