CVE-2026-34943
Description
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.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
wasmtimecrates.io | < 24.0.7 | 24.0.7 |
wasmtimecrates.io | >= 25.0.0, < 36.0.7 | 36.0.7 |
wasmtimecrates.io | >= 37.0.0, < 42.0.2 | 42.0.2 |
wasmtimecrates.io | >= 43.0.0, < 43.0.1 | 43.0.1 |
Affected products
1Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
4- github.com/advisories/GHSA-m758-wjhj-p3jqghsaADVISORY
- github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m758-wjhj-p3jqnvdVendor AdvisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2026-34943ghsaADVISORY
- rustsec.org/advisories/RUSTSEC-2026-0085.htmlghsaWEB
News mentions
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