Vulnerability · Published Oct 29, 2026 · Assigned by VulnCheck
CVE-2026-119140Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Host Panic via thread.yield
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 11% of all known vulnerabilities).
Severity (CVSS 3.1)4.8Medium
Exploit odds (30 days)0.2%top 89.0% 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 malicious components to panic the host via thread.yield in start functions. Attackers can supply a component whose start function calls an async-lowered import then thread.yield, causing an undisposed fiber drop that crashes embedders.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:24.04:LTS | rust-wasmtime | no fix listed | UBUNTU-CVE-2026-119140 |
| Ubuntu:26.04:LTS | rust-wasmtime | no fix listed | UBUNTU-CVE-2026-119140 |
| Ubuntu:26.10 | rust-wasmtime | no fix listed | UBUNTU-CVE-2026-119140 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| bytecodealliance | wasmtime | 46.0.0 – before 48.0.649.0.0 – before 49.0.3 |
Weakness: CWE-372 · 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-5hhx-4wrr-3j9g) vendor-advisory
- VulnCheck Advisory: Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Host Panic via thread.yield third-party-advisory