MEDIUM 6.5 GitHub
CVE-2026-58494
Wasmtime: WASI hard links bypass wasmtime-wasi's FilePerms for destination
## Summary
Wasmtime's WASI filesystem implementation lets a guest with a read-only source file capability overwrite that file by hard-linking it into another preopen that allows file writes. An attacker who can run a WASI guest can bypass `WasiCtxBuilder` per-preopen `FilePerms` and modify host files that were exposed as `FilePerms::READ`.
This attack is possible through the wasip1, wasip2, and wasip3 interfaces to the WASI filesystem.
This attack is also possible through an indirection of re
Affected Products
- rust/wasmtime-wasi < 24.0.11
- rust/wasmtime-wasi >= 25.0.0, < 36.0.12
- rust/wasmtime-wasi >= 37.0.0, < 45.0.3
- rust/wasmtime-wasi >= 46.0.0, < 46.0.1
References
- https://github.com/advisories/GHSA-4ch3-9j33-3pmj
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-4ch3-9j33-3pmj
- https://nvd.nist.gov/vuln/detail/CVE-2026-58494
- https://github.com/bytecodealliance/wasmtime/pull/13725
This medium severity vulnerability with a CVSS score of 6.5 was published on 2026-10-16 via GitHub. Affected: rust/wasmtime-wasi < 24.0.11, rust/wasmtime-wasi >= 25.0.0, < 36.0.12, rust/wasmtime-wasi >= 37.0.0, < 45.0.3 and 1 more.
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