Auth bypass in Bytecodealliance Wasmtime
CVE-2026-58494
Wasmtime is a runtime for WebAssembly. Prior to 24.0.11, 36.0.12, 45.0.3, and 46.0.1, wasmtime-wasi hard-link creation and renaming check directory permissions but not matching FilePerms on source and destination preopens, allowing a WASI guest with a read-only source file capability to overwrite host files exposed as FilePerms::READ through wasip1, wasip2, or wasip3 filesystem interfaces. This issue is fixed in versions 24.0.11, 36.0.12, 45.0.3, and 46.0.1.
EPSS: 0.001 (2.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N.
Affected products
- Bytecodealliance Wasmtime — versions < 24.0.11, >= 25.0.0, < 36.0.12, >= 37.0.0, < 45.0.3
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-58494?
- CVE-2026-58494 is a medium-severity vulnerability in Bytecodealliance Wasmtime, classified under Improper Preservation of Permissions. CVSS score: 6.5/10. Published 2026-07-08.
- How severe is CVE-2026-58494?
- Medium severity. CVSS v3 base score is 6.5 out of 10.