CVE-2026-115381

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

State: Published
Severity: 5.9 Medium
Published: Oct 22, 2026
Updated: Oct 26, 2026
Reserved: Oct 22, 2026

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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.

Scores

CVSS	Score	Vector	Source
4.0	5.9 Medium	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	VulnCheck
3.1	4.8 Medium	CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H	VulnCheck

Weaknesses

CWE-770 Allocation of Resources Without Limits or Throttling

Affected Products

Product	Versions
wasmtimebytecodealliance	before 36.0.17Affected 36.0.17Not affected 37.0.0 to before 48.0.4Affected 48.0.4Not affected 49.0.0 to before 49.0.2Affected 49.0.2Not affected

References

GitHub Security Advisory (GHSA-gqmc-89g8-p25r)vendor-advisory
VulnCheck Advisory: 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-zeroesthird-party-advisory

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