Improper Check or Handling of Exceptional Conditions in Wasmtime - CVE-2026-27572
Published: April 23, 2026
Vulnerability identifier: #VU127043
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-27572
CWE-ID: CWE-703
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper handling of excessive capacity in wasi:http/types.fields in the wasmtime-wasi-http crate when adding too many header fields to a set of headers. A remote user can add excessive fields to a wasi:http/types.fields instance to cause a denial of service.
Panicking in the WASI implementation can affect embedders.
Affected software
Wasmtime
How to mitigate CVE-2026-27572
Install security update from vendor's website.
Wasmtime - addressed in versions 24.0.6, 36.0.6, 40.0.4, 41.0.4, 42.0.0