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-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.

Score

CVSS 4.0 6.9 Medium

Status

Deferred - disclosure@vulncheck.com

Published

2026-10-22

Last modified

2026-10-22

Weaknesses

CWE-400

Affected products

• Wasmtime (Bytecodealliance)

References

• https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-c9gc-w9vx-w86p
• https://www.vulncheck.com/advisories/wasmtime-before-36.0.16-37.0.0-before-48.0.3-and-49.0.0-before-49.0.1-memory-exhau…