Bug 2451798 (CVE-2026-33490) - CVE-2026-33490 h3: H3: Information disclosure due to incorrect path prefix validation
Summary: CVE-2026-33490 h3: H3: Information disclosure due to incorrect path prefix va...
Keywords:
Status: NEW
Alias: CVE-2026-33490
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2452017 2452018
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-03-26 18:01 UTC by OSIDB Bzimport
Modified: 2026-03-26 22:59 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-03-26 18:01:54 UTC
H3 is a minimal H(TTP) framework. In versions 2.0.0-0 through 2.0.1-rc.16, the `mount()` method in h3 uses a simple `startsWith()` check to determine whether incoming requests fall under a mounted sub-application's path prefix. Because this check does not verify a path segment boundary (i.e., that the next character after the base is `/` or end-of-string), middleware registered on a mount like `/admin` will also execute for unrelated routes such as `/admin-public`, `/administrator`, or `/adminstuff`. This allows an attacker to trigger context-setting middleware on paths it was never intended to cover, potentially polluting request context with unintended privilege flags. Version 2.0.2-rc.17 contains a patch.


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