Improper Preservation of Permissions in Wasmtime - CVE-2026-58494
Published: August 1, 2026
Vulnerability identifier: #VU140662
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-58494
CWE-ID: CWE-281
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to modify host files exposed as read-only.
The vulnerability exists due to improper preservation of permissions in wasmtime-wasi WASI filesystem hard link and rename operations when creating a hard link or renaming a hard link across preopens with different file permissions. A local user can create or move a hard link into a writable preopen and open it for writing to modify host files exposed as read-only.
Only embeddings that use a combination of DirPerms::MUTATE with FilePerms::READ and a second preopen with higher file permissions are vulnerable. The issue affects the wasip1, wasip2, and wasip3 filesystem interfaces.
Affected software
Wasmtime
How to mitigate CVE-2026-58494
Install security update from vendor's website.
Wasmtime - addressed in versions 24.0.11, 36.0.12, 45.0.3, 46.0.1