CVE-2025-11233 in Rust
Summary
by MITRE • 10/01/2025
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.
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Analysis
by VulDB Data Team • 04/22/2026
The vulnerability described in CVE-2025-11233 affects the Rust programming language's handling of path separators within the tier 3 Cygwin target implementation. This issue specifically impacts versions of Rust between 1.87.0 and 1.89.0, where the standard library's Path API fails to properly process path components separated by backslashes on the Cygwin target platform. The fundamental flaw lies in the incorrect interpretation of path separators, which creates a divergence between how the system expects paths to be structured and how they are actually processed, creating potential security implications for applications that rely on path validation.
The technical nature of this vulnerability stems from the improper handling of path normalization within the standard library's Path API implementation for the x86_64-pc-cygwin target. When applications compiled for this target encounter paths containing backslash separators, the standard library ignores components separated by these characters, effectively truncating or corrupting the path structure. This behavior creates a path traversal vulnerability because the system does not properly validate or normalize paths, allowing attackers to potentially bypass intended path restrictions. The issue is particularly concerning as it affects the core path handling mechanisms that applications depend upon for filesystem operations and security validation.
From an operational perspective, this vulnerability represents a medium-severity risk that primarily affects users who have manually compiled the Cygwin target from source. The vulnerability's impact is limited by the fact that the tier 3 Cygwin target is not distributed through standard Rust distribution channels such as Rustup, and requires explicit manual compilation. This restriction significantly reduces the attack surface, as the vast majority of Rust developers who use pre-built binaries are unaffected by this issue. However, for those who do compile this target, the vulnerability could enable malicious filesystem operations through path traversal attacks, potentially allowing unauthorized access to restricted directories or files.
The mitigation for this vulnerability is straightforward as it has been resolved in Rust 1.89.0 through enhanced path handling that properly supports both Win32 and Unix style path formats. The fix ensures that the standard library correctly processes path components regardless of separator type, thereby eliminating the path traversal risk. Organizations should update to Rust 1.89.0 or later to address this vulnerability, particularly those who have manually compiled the Cygwin target. Additionally, users should be aware that the tier 1 MinGW target remains unaffected, and that only users who have explicitly built the Cygwin target from source are at risk, making this vulnerability's practical impact quite limited in the broader Rust ecosystem.
This vulnerability aligns with CWE-22 Path Traversal and CWE-77 Path Traversal issues, where improper path handling creates opportunities for attackers to access unauthorized filesystem locations. The ATT&CK framework would classify this under T1059 Command and Scripting Interpreter and potentially T1566 Phishing, as the vulnerability could enable attackers to manipulate filesystem access patterns through crafted path inputs. The specific nature of this vulnerability also demonstrates the importance of proper path normalization in cross-platform development environments, particularly in tier 3 targets where the standard library implementation may not receive the same level of testing and validation as first-party targets.