CVE-2026-34943: Wasmtime panics when lifting `flags` component value
bytecodealliance · wasmtime
Affected: bytecodealliance wasmtime · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 27% of scored CVEs
DescriptionCVE.org
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 products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- bytecodealliance · wasmtime< 24.0.7; >= 25.0.0, < 36.0.7; >= 37.0.0, < 42.0.2; >= 43.0.0, < 44.0.1
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- bytecodealliance
- Published
- April 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-34943 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.