All vulnerabilities
CVE-2026-115381GHSA-gqmc-89g8-p25r

Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 Unbounded Host Memory Allocation via SinkOutputStream write-zeroes

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)0.21%Chance of exploitation activity in the next 30 days, higher than 10% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in36.0.17Also 48.0.4, 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 before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains an unbounded memory allocation in the wasmtime-wasi WASIp2 write-zeroes method of SinkOutputStream, the default stream used when stdout/stderr are not configured. A malicious WebAssembly guest can request huge zero-filled writes, exhausting host memory and causing denial of service.

Text from CVE List

Affected versions 6

  • wasmtimeaffected: all versions before 36.0.17CVE List
  • wasmtimeunaffected: 36.0.17CVE List
  • wasmtimeaffected: 37.0.0 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