Vulnerability · Published Oct 29, 2026 · Assigned by VulnCheck

CVE-2026-119132Wasmtime 49.0.0 before 49.0.3 Host Panic via Overlapping String Transcode in Fused Adapter

Medium 4.8

In plain English

A medium-severity security flaw 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 0.2% (higher than 12% of all known vulnerabilities).

Severity (CVSS 3.1)4.8Medium

Exploit odds (30 days)0.2%top 88.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Wasmtime from 49.0.0 before 49.0.3 contains a denial-of-service vulnerability that allows a WebAssembly guest to trigger a host panic by transcoding overlapping strings in fused adapters. Attackers can make a same-instance component-to-component call transferring a string whose source and destination alias each other, crashing the host instead of raising a trap.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Ubuntu:24.04:LTS	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-119132
Ubuntu:26.04:LTS	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-119132
Ubuntu:26.10	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-119132

Affected products (as reported)

Vendor	Product	Versions
bytecodealliance	wasmtime	49.0.0 – before 49.0.3

Weakness: CWE-617 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H

References

GitHub Security Advisory (GHSA-54p9-vhhq-8f7q) vendor-advisory
VulnCheck Advisory: Wasmtime 49.0.0 before 49.0.3 Host Panic via Overlapping String Transcode in Fused Adapter third-party-advisory