CVE-2026-115381 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
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-115381?
CVE-2026-115381 is a medium-severity vulnerability in bytecodealliance wasmtime, published on 22 Oct 2026.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2026-115381?
1 open source package ship an affected version, including wasmtime-wasi.
| Package | Affected | Fixed in |
|---|---|---|
wasmtime-wasi crates.io | From 0.0.0-0 | 36.0.17, 48.0.4, 49.0.2 |
How do I fix CVE-2026-115381?
Upgrade wasmtime-wasi to a fixed version for your release line: 36.0.17, 48.0.4 or 49.0.2.
Is CVE-2026-115381 being exploited?
There is no known exploitation of CVE-2026-115381 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-115381, GHSA-gqmc-89g8-p25r, GHSA-m3j5-9cx2-7c68, RUSTSEC-2026-0322, UBUNTU-CVE-2026-115381.