GitHub Advisoryadvisory · crates.io
GHSA-3p27-qvp9-27qf Wasmtime has a leak in WASIp1 `fd_renumber` implementation
LOW
Official page ↗
- Aliases
- CVE-2026-54786
- Ecosystem
- crates.io
- Packages
- wasmtime-wasi
- Severity
- Low
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L
- Weaknesses
- CWE-400
- Reviewed
- 2026-08-26
Affected packages
• crates.io wasmtime-wasi: < 24.0.10 → fixed in 24.0.10
• crates.io wasmtime-wasi: >= 45.0.0, < 45.0.2 → fixed in 45.0.2
• crates.io wasmtime-wasi: >= 25.0.0, < 36.0.11 → fixed in 36.0.11
• crates.io wasmtime-wasi: >= 37.0.0, < 44.0.3 → fixed in 44.0.3
Description
Impact
Wasmtime's native implementation of WASIp1 suffers from a leak in the `fd_renumber` function where the file descriptor being renumbered to is not properly closed. Wasmtime's implementation erroneously only updated the table of descriptors for WASIp1 and didn't update the underlying table of descriptors used by the host. This behavior means that while `fd_renumber` works correctly from a guest's perspective it ends up leaking resources in the host that aren't cleaned up until the corresponding `Store` is destroyed. This means that guests can, in a loop, use `fd_renumber` to cause hosts to exhaust resources or exhaust file descriptors.
This bug only affects the native implementation of WASIp1. This means that only runtimes which load core wasm modules and expose `fd_renumber` are affected. Runtimes are additionally only affected if they expose the ability to acquire a file descriptor, such as opening a file. For runtimes that deny access to files they are unaffected.
Patches
Wasmtime 24.0.10, 36.0.11, 44.0.3, and 45.0.2 have been released which fix this issue.
Workarounds
There are no workarounds for this issue and hosts are recommended to update.
Related
Alias · CVE (1)
- CVE-2026-54786 Wasmtime is a runtime for WebAssembly. vulnerability
Weakness · CWE (1)
- CWE-400 Uncontrolled Resource Consumption weakness
References
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-3p27-qvp9-27qf web
- https://nvd.nist.gov/vuln/detail/CVE-2026-54786 advisory
- https://github.com/bytecodealliance/wasmtime/pull/13650 web
- https://github.com/bytecodealliance/wasmtime/commit/100bfe27253d2ce5154ddddf66d06e30f3fa6824 web
- https://github.com/bytecodealliance/wasmtime/commit/36b305d827149ac0336ddcbc0a378c303339d195 web
- https://github.com/bytecodealliance/wasmtime/commit/72493b11ed5df382c92a9dfb8b6bc064e471f1cd web
- https://github.com/bytecodealliance/wasmtime/commit/e9fbe974c9698edef117323d981e13caf2097c13 web
- https://github.com/bytecodealliance/wasmtime/commit/f069f125cb77a4a3dced19a77d73790610678622 web
- https://github.com/bytecodealliance/wasmtime package
- https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.10 web
- https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.11 web
- https://github.com/bytecodealliance/wasmtime/releases/tag/v44.0.3 web
- https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.2 web
- https://rustsec.org/advisories/RUSTSEC-2026-0182.html web