Bug 2529162 (CVE-2026-86250) - CVE-2026-86250 h3: h3: Denial of Service via unbounded chunked cookie processing
Summary: CVE-2026-86250 h3: h3: Denial of Service via unbounded chunked cookie processing
Keywords:
Status: NEW
Alias: CVE-2026-86250
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-06 12:11 UTC by OSIDB Bzimport
Modified: 2026-09-18 08:20 UTC (History)
0 users

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-09-06 12:11:51 UTC 
h3 versions before 2.0.1-rc.18 fail to validate the chunk count parsed from user-controlled cookie values in setChunkedCookie() and deleteChunkedCookie() functions. Attackers can send a crafted cookie header with an extremely large chunk count to trigger an O(n²) cleanup loop that hangs the server process.
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