CVE-2026-34943

April 9, 2026, 7:16 p.m.

5.6
Medium

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.

Product(s) Impacted

Vendor Product Versions
Wasmtime
  • Wasmtime
  • 24.0.7, 36.0.7, 42.0.2, 43.0.1

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-248
Uncaught Exception
An exception is thrown from a function, but it is not caught.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a wasmtime wasmtime 24.0.7 / / / / / / /
a wasmtime wasmtime 36.0.7 / / / / / / /
a wasmtime wasmtime 42.0.2 / / / / / / /
a wasmtime wasmtime 43.0.1 / / / / / / /

References

https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m758-wjhj-p3jq

Tags

[email protected]
CWE-248
2026-04-09
CVE-2026-34943

CVSS Score

5.6 / 10

CVSS Data - 4.0

  • Attack Vector: NETWORK
  • Attack Complexity: HIGH
  • Attack Requirements: PRESENT
  • Privileges Required: HIGH
  • User Interaction: ACTIVE
  • Scope:
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: HIGH
  • Exploit Maturity: NOT_DEFINED

    • CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

    View Vector String

Timeline

Published: April 9, 2026, 7:16 p.m.
Last Modified: April 9, 2026, 7:16 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.