CVE-2026-115388

Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 Memory Exhaustion DoS via wasmtime-wasi-http Outgoing Body Write

State: Published
Severity: 6.9 Medium
Published: Oct 22, 2026
Updated: Oct 29, 2026
Reserved: Oct 22, 2026

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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.

Scores

CVSS	Score	Vector	Source
4.0	6.9 Medium	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	VulnCheck
3.1	6.2 Medium	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	VulnCheck

Weaknesses

CWE-400 Uncontrolled Resource Consumption

Affected Products

Product	Versions
wasmtimebytecodealliance	before 36.0.16Affected 36.0.16Not affected 37.0.0 to before 48.0.3Affected 48.0.3Not affected 49.0.0 to before 49.0.1Affected 49.0.1Not affected

References

GitHub Security Advisory (GHSA-c9gc-w9vx-w86p)vendor-advisory
VulnCheck Advisory: Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 Memory Exhaustion DoS via wasmtime-wasi-http Outgoing Body Writethird-party-advisory

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