CVE-2026-0810: gix-date Invalid UTF-8 Vulnerability

CVE-2026-0810 Overview

A vulnerability has been identified in gix-date, a component of the Gitoxide project. The gix_date::parse::TimeBuf::as_str function can generate strings containing invalid non-UTF8 characters, violating the internal safety invariants of the TimeBuf component. This issue can lead to undefined behavior when these malformed strings are subsequently processed, potentially resulting in application instability or other unforeseen consequences.

Critical Impact

This vulnerability violates Rust's UTF-8 string safety guarantees, leading to undefined behavior that could cause application crashes, memory corruption, or unpredictable application states in software using the gix-date crate.

Affected Products

• gix-date Rust crate (part of Gitoxide project)
• Applications using gix-date for date parsing operations
• Rust projects dependent on Gitoxide's date handling functionality

Discovery Timeline

• 2026-01-26 - CVE-2026-0810 published to NVD
• 2026-01-27 - Last updated in NVD database

Technical Details for CVE-2026-0810

Vulnerability Analysis

The vulnerability exists within the gix_date::parse::TimeBuf::as_str function in the gix-date crate, which is part of the broader Gitoxide project—a pure Rust implementation of Git. The function is designed to convert an internal time buffer structure into a string representation. However, under certain conditions, the function can produce strings containing bytes that do not conform to valid UTF-8 encoding sequences.

In Rust, the str type has a fundamental invariant: all str values must contain valid UTF-8 encoded data. This invariant is critical for memory safety and correct string handling throughout the Rust ecosystem. When as_str returns invalid UTF-8 data while claiming to return a valid str, it breaks this invariant, leading to undefined behavior.

The consequences of this violation can manifest in various ways depending on how the malformed string is subsequently used. String operations that assume valid UTF-8 may produce incorrect results, crash, or in worst-case scenarios, lead to memory safety issues. This is classified under CWE-135 (Incorrect Calculation of Multi-Byte String Length), as the vulnerability involves improper handling of character encoding boundaries.

Root Cause

The root cause stems from improper validation or construction of UTF-8 strings within the TimeBuf structure's as_str method. When constructing the string representation from raw byte data, the function fails to ensure that all bytes form valid UTF-8 sequences before returning them as a str type. This could occur during date parsing when handling edge cases, malformed input data, or certain timezone representations that produce byte sequences incompatible with UTF-8 encoding requirements.

Attack Vector

This is a local attack vector vulnerability. An attacker would need to provide specially crafted date input to an application using the gix-date crate. When the application parses this input and subsequently calls TimeBuf::as_str(), the invalid UTF-8 data is generated. The exploitation scenario requires:

1. The target application must use gix-date for date parsing functionality
2. The attacker must be able to supply malformed date strings as input
3. The application must process the returned string in a way that triggers the undefined behavior

Since this requires local interaction with date parsing functionality, the vulnerability is most concerning for applications that process untrusted date strings, such as Git clients, version control tools, or any software integrating Gitoxide components for date handling.

Detection Methods for CVE-2026-0810

Indicators of Compromise

• Unexpected application crashes or panics during date parsing operations
• Memory corruption symptoms in applications using gix-date functionality
• Log entries showing invalid UTF-8 string errors or encoding failures
• Rust panic messages referencing gix_date::parse::TimeBuf or string validation failures

Detection Strategies

• Monitor application logs for Rust panics or undefined behavior indicators related to string operations
• Implement runtime UTF-8 validation checks before processing strings from TimeBuf::as_str() as a defensive measure
• Use Rust's built-in testing frameworks to validate UTF-8 compliance of date parsing outputs
• Deploy SentinelOne agents to detect anomalous application behavior patterns indicative of memory safety violations

Monitoring Recommendations

• Enable verbose logging for date parsing operations in applications using gix-date
• Implement automated dependency scanning to identify vulnerable gix-date versions in your Rust projects
• Monitor for unusual process crashes or restarts in services that handle date parsing
• Utilize cargo-audit to continuously scan Rust dependencies for known security advisories including RUSTSEC-2025-0140

How to Mitigate CVE-2026-0810

Immediate Actions Required

• Review your Rust projects for dependencies on the gix-date crate using cargo tree -p gix-date
• Check the RustSec Advisory RUSTSEC-2025-0140 for patched version information
• Update gix-date to the latest patched version as recommended in the security advisory
• Audit code paths that consume string output from TimeBuf::as_str() for potential undefined behavior handling

Patch Information

Consult the Gitoxide Issue #2305 Discussion for detailed patch information and the gix-date crate documentation for the latest secure version. The Red Hat CVE-2026-0810 Advisory and Red Hat Bug Report #2427057 provide additional guidance for Red Hat-based systems.

Workarounds

• Implement defensive UTF-8 validation on any strings obtained from TimeBuf::as_str() before further processing
• Consider using alternative date parsing libraries temporarily until patches are applied
• Add input validation to reject potentially malformed date strings before they reach the gix-date parser
• Implement application-level error handling to gracefully manage potential undefined behavior scenarios

# Check for vulnerable gix-date dependency in your Rust project
cargo audit

# List all dependencies on gix-date
cargo tree -p gix-date

# Update gix-date to the latest version
cargo update -p gix-date