GitHub Advisoryadvisory · crates.io
GHSA-fm79-3f68-h2fc Wasmtime CLI is vulnerable to host panic through its fd_renumber function
LOW
Official page ↗
- Aliases
- CVE-2025-53901
- Ecosystem
- crates.io
- Packages
- wasmtime-wasi, wasmtime
- Severity
- Low
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
- Weaknesses
- CWE-672
- Reviewed
- 2025-07-18
Affected packages
• crates.io wasmtime-wasi: < 24.0.4 → fixed in 24.0.4
• crates.io wasmtime-wasi: >= 25.0.0, < 33.0.2 → fixed in 33.0.2
• crates.io wasmtime-wasi: >= 34.0.0, < 34.0.2 → fixed in 34.0.2
• crates.io wasmtime: >= 10.0.0, < 24.0.4 → fixed in 24.0.4
• crates.io wasmtime: >= 33.0.0, < 33.0.2 → fixed in 33.0.2
• crates.io wasmtime: >= 34.0.0, < 34.0.2 → fixed in 34.0.2
Description
Summary
A bug in Wasmtime's implementation of the WASIp1 set of import functions can lead to a WebAssembly guest inducing a panic in the host (embedder).
The specific bug is triggered by calling `path_open` after calling `fd_renumber` with either:
• two equal argument values
• second argument being equal to a previously-closed file descriptor number value
The corrupt state introduced in `fd_renumber` will lead to the subsequent opening of a file descriptor to panic. This panic cannot introduce memory unsafety or allow WebAssembly to break outside of its sandbox, however. There is no possible heap corruption or memory unsafety from this panic.
This bug is in the implementation of Wasmtime's `wasmtime-wasi` crate which provides an implementation of WASIp1. The bug requires a specially crafted call to `fd_renumber` in addition to the ability to open a subsequent file descriptor. Opening a second file descriptor is only possible when a preopened directory was provided to the guest, and this is common amongst embeddings. A panic in the host is considered a denial-of-service vector for WebAssembly embedders and is thus a security issue in Wasmtime.
This bug does not affect WASIp2 and embedders using components.
Patches
In accordance with Wasmtime's release process patch releases are available as 24.0.4, 33.0.2, and 34.0.2. Users of other release of Wasmtime are recommended to move to a supported release of Wasmtime.
Workarounds
Embedders who are using components or are not providing guest access to create more file descriptors (e.g. via a preopened filesystem directory) are not affected by this issue. Otherwise there is no workaround at this time and affected embeddings are recommended to update to a patched version which will not cause a panic in the host.
Related
Alias · CVE (1)
- CVE-2025-53901 Wasmtime is a runtime for WebAssembly. vulnerability
Weakness · CWE (1)
- CWE-672 Operation on a Resource after Expiration or Release weakness
References
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-fm79-3f68-h2fc web
- https://nvd.nist.gov/vuln/detail/CVE-2025-53901 advisory
- https://github.com/bytecodealliance/wasmtime/pull/11277 web
- https://github.com/bytecodealliance/wasmtime/pull/11278 web
- https://github.com/bytecodealliance/wasmtime/pull/11279 web
- https://github.com/bytecodealliance/wasmtime/pull/11281 web
- https://docs.wasmtime.dev/security-what-is-considered-a-security-vulnerability.html web
- https://docs.wasmtime.dev/stability-release.html web
- https://github.com/WebAssembly/WASI/blob/e1aa1cae4dda4c1f70f23fe11e922aae92f240a8/legacy/preview1/witx/wasi_snapshot_preview1.witx#L245-L260 web
- https://github.com/bytecodealliance/wasmtime package
- https://github.com/bytecodealliance/wasmtime/blob/037a6edadbc225decbea00a551aabf04203717d9/crates/wasi/src/preview1.rs#L1824-L1836 web
- https://rustsec.org/advisories/RUSTSEC-2025-0046.html web