Bug 2457005 (CVE-2026-34943) - CVE-2026-34943 Wasmtime: Wasmtime: Denial of Service due to malformed flags-typed component model value processing
Summary: CVE-2026-34943 Wasmtime: Wasmtime: Denial of Service due to malformed flags-t...
Keywords:
Status: NEW
Alias: CVE-2026-34943
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2457174
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-09 19:02 UTC by OSIDB Bzimport
Modified: 2026-04-09 22:54 UTC (History)
0 users

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Description OSIDB Bzimport 2026-04-09 19:02:37 UTC
Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the set of flags the component model specifies that these bits should be ignored but Wasmtime will panic when this value is lifted. This panic only affects wasmtime's implementation of lifting into Val, not when using the flags! macro. This additionally only affects flags-typed values which are part of a WIT interface. This has the risk of being a guest-controlled panic within the host which Wasmtime considers a DoS vector. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.


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