All vulnerabilities
CVE-2026-115383GHSA-cfhf-m2cr-62wj

Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 GC Heap Corruption via Tag Imports

bytecodealliance wasmtime
Open in ThreatlineRecord JSON
CVSS
5.9Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.18%Chance of exploitation activity in the next 30 days, higher than 7% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in48.0.4Also 49.0.2CVE List
Published22 Oct 2026Updated 22 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains an improper validation vulnerability that accepts components whose core modules import WebAssembly tags with a subtype of the original type. Malicious guests can mis-type exception object payloads to corrupt the GC heap, causing Wasmtime to panic when the exceptions proposal is enabled.

Text from CVE List

Affected versions 4

  • wasmtimeaffected: 47.0.0 before 48.0.4CVE List
  • wasmtimeunaffected: 48.0.4CVE List
  • wasmtimeaffected: 49.0.0 before 49.0.2CVE List
  • wasmtimeunaffected: 49.0.2CVE List

References 2