Rust standard library didn't detect all path separators on Cygwin

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-11233
StatePUBLISHED
Assignerrust
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-10-01 17:15:38 UTC
Updated2026-10-09 09:10:00 UTC
DescriptionStarting 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.

Risk And Classification

Primary CVSS: v4.0 6.3 MEDIUM from 986d4109-89ea-491f-99fd-a8e4803919bd

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:L/U:Green

EPSS: 0.005170000 probability, percentile 0.422600000 (date 2026-10-11)

Problem Types: CWE-22 | CWE-22 CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

VersionSourceTypeScoreSeverityVector
4.0986d4109-89ea-491f-99fd-a8e4803919bdSecondary6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/C...
4.0CNACVSS6.3MEDIUMCVSS: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/...

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
Low
Sub Conf.
Low
Sub Integrity
Low
Sub Availability
Low

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:L/U:Green

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Rust Project Std affected 1.87.0 1.89.0 semver Windows

References

ReferenceSourceLinkTags
github.com/rust-lang/rust/pull/141864 986d4109-89ea-491f-99fd-a8e4803919bd github.com
groups.google.com/g/rustlang-security-announcements/c/oT9zCvLLYkw 986d4109-89ea-491f-99fd-a8e4803919bd groups.google.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: We recommend users of Cygwin targets to upgrade to 1.89.0 or a later version.

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