All vulnerabilities
CVE-2026-115384GHSA-32h6-97mm-8q3c

Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 Stack Buffer Overflow

bytecodealliance wasmtime
Open in ThreatlineRecord JSON
CVSS
9.4Critical
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.31%Chance of exploitation activity in the next 30 days, higher than 22% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in48.0.4Also 49.0.2CVE List
Published22 Oct 2026Updated 23 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 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a stack buffer overflow vulnerability that allows malicious guests to write ~16KB to the native stack via unvalidated async callback result types. Attackers can supply components with mistyped component-model-async callback functions to overwrite return addresses, crashing the host or escaping the sandbox.

Text from CVE List

Affected versions 6

  • wasmtimeaffected: 39.0.0 before 48.0.4CVE List
  • wasmtimeunaffected: 48.0.4CVE List
  • wasmtimeaffected: 49.0.0 before 49.0.2CVE List
  • wasmtimeunaffected: 49.0.2CVE List
  • wasmtime, rust>= 39.0.0, < 48.0.4GitHub
  • wasmtime, rust>= 49.0.0, < 49.0.2GitHub

References 2