CVE-2026-115388 wasmtime-wasi-http in Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not enforce the wasi:io/streams check-wri
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-115388?
CVE-2026-115388 is a medium-severity vulnerability in bytecodealliance wasmtime, published on 22 Oct 2026.
Official description
wasmtime-wasi-http in Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not enforce the wasi:io/streams check-write allowance for WASIp2 outgoing HTTP bodies, so oversized writes succeed instead of trapping. A malicious guest can pass large buffers to write on outgoing-body resources, holding host allocations for the store's lifetime and exhausting host memory.
Weakness: CWE-400
Which versions are affected by CVE-2026-115388?
1 open source package ship an affected version, including wasmtime-wasi-http.
| Package | Affected | Fixed in |
|---|---|---|
wasmtime-wasi-http crates.io | From 0.0.0-0 | 36.0.16, 48.0.3, 49.0.1 |
How do I fix CVE-2026-115388?
Upgrade wasmtime-wasi-http to a fixed version for your release line: 36.0.16, 48.0.3 or 49.0.1.
Is CVE-2026-115388 being exploited?
There is no known exploitation of CVE-2026-115388 in the wild and no public exploit code.
Sources
Also known as GHSA-7qg7-h7wh-p6q8, GHSA-c9gc-w9vx-w86p, RUSTSEC-2026-0313, UBUNTU-CVE-2026-115388.