Vulnerability · Published Oct 29, 2026 · Assigned by VulnCheck

CVE-2026-119143Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Panic via Zero-Length Stream Writes

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 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability that allows guest code to trigger a host panic through out-of-bounds zero-length stream operations. Malicious guests can perform zero-length component model stream reads or writes with unvalidated addresses, causing Direct{Source,Destination}::remaining to panic and crash WASIp3 embedders.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Ubuntu:24.04:LTS	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-119143
Ubuntu:26.04:LTS	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-119143
Ubuntu:26.10	rust-wasmtime	no fix listed	UBUNTU-CVE-2026-119143

Affected products (as reported)

Vendor	Product	Versions
bytecodealliance	wasmtime	46.0.0 – before 48.0.649.0.0 – before 49.0.3

Weakness: CWE-129 · 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-93g3-36p8-x2gc) vendor-advisory
VulnCheck Advisory: Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Panic via Zero-Length Stream Writes third-party-advisory