Vulnerability · Published Oct 22, 2026 · Assigned by VulnCheck

CVE-2026-115380Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 Fuel Limit Bypass DoS via WASI Preview 0 poll_oneoff

Medium 4.0

In plain English

A medium-severity resource allocation without limits in wasmtime from bytecodealliance. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.0Medium

Exploit odds (30 days)0.1%top 98.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains a denial of service vulnerability in the wasmtime-wasi WASI preview 0 poll_oneoff adapter, which performs O(n) host work per subscription without consuming or checking fuel. Malicious guest modules can pass many subscriptions to force long-running host computation that ignores configured fuel limits.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:13	rust-wasmtime	no fix listed	DEBIAN-CVE-2026-115380
Debian:14	rust-wasmtime	36.0.20+dfsg-1	DEBIAN-CVE-2026-115380
Ubuntu:24.04:LTS	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-115380
Ubuntu:26.04:LTS	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-115380
Ubuntu:26.10	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-115380

Affected products (as reported)

Vendor	Product	Versions
bytecodealliance	wasmtime	0 – before 36.0.1737.0.0 – before 48.0.449.0.0 – before 49.0.2

Weakness: CWE-770 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

GitHub Security Advisory (GHSA-j366-h8gg-77pm) vendor-advisory
VulnCheck Advisory: Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 Fuel Limit Bypass DoS via WASI Preview 0 poll_oneoff third-party-advisory