CVE-2026-115388

Medium

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.

SeverityMedium

CVSS6.2

Exploit probability—

ProductBytecodealliance Wasmtime

PublishedOct 22, 2026

First seenOct 22, 2026

Weakness typeCWE-400Uncontrolled resource consumption

How to fix

Update

bytecodealliance wasmtime36.0.16, 48.0.3, 49.0.1 or later

Vendor advisories

github.com/bytecodealliance/wasmtime/security/advisories/GHSA-c9gc-w9vx-w86p

Affected products

Product	Affected versions	Fixed in
bytecodealliance wasmtime	v < 36.0.16, 37.0.0 ≤ v < 48.0.3, 49.0.0 ≤ v < 49.0.1	36.0.16, 48.0.3, 49.0.1

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