All vulnerabilities
CVE-2026-115389GHSA-jqpg-j7w6-42pr

Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 Denial of Service via Val API

bytecodealliance wasmtime
Open in ThreatlineRecord JSON
CVSS
1.0Low
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.15%Chance of exploitation activity in the next 30 days, higher than 4% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in36.0.16Also 48.0.3, 49.0.1CVE 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 before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not adequately account for host allocations when lifting guest values through the dynamically-typed Val API, bypassing the hostcall fuel limit. A malicious WebAssembly guest can return crafted values that allocate at least ~100x more host memory than tracked, causing denial of service.

Text from CVE List

Affected versions 9

  • wasmtimeaffected: all versions before 36.0.16CVE List
  • wasmtimeunaffected: 36.0.16CVE List
  • wasmtimeaffected: 37.0.0 before 48.0.3CVE List
  • wasmtimeunaffected: 48.0.3CVE List
  • wasmtimeaffected: 49.0.0 before 49.0.1CVE List
  • wasmtimeunaffected: 49.0.1CVE List
  • wasmtime, rust<= 36.0.15GitHub
  • wasmtime, rust>= 37.0.0, <= 48.0.2GitHub
  • wasmtime, rust49.0.0GitHub

References 2