CVE-2025-48386: Git Wincred Buffer Overflow Vulnerability

CVE-2025-48386 Overview

A buffer overflow vulnerability has been discovered in Git's wincred credential helper on Windows systems. The wincred credential helper uses a static buffer (target) as a unique key for storing and comparing against internal storage. This credential helper does not properly bounds check the available space remaining in the buffer before appending to it with wcsncat(), leading to potential buffer overflows that could allow an attacker to read sensitive credential information from memory.

Critical Impact

Buffer overflow in Git's Windows credential helper could expose sensitive authentication credentials stored in memory, potentially compromising repository access and source code security.

Affected Products

• Git versions prior to v2.43.7
• Git versions v2.44.x prior to v2.44.4
• Git versions v2.45.x prior to v2.45.4
• Git versions v2.46.x prior to v2.46.4
• Git versions v2.47.x prior to v2.47.3
• Git versions v2.48.x prior to v2.48.2
• Git versions v2.49.x prior to v2.49.1
• Git versions v2.50.x prior to v2.50.1

Discovery Timeline

• 2025-07-08 - CVE-2025-48386 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2025-48386

Vulnerability Analysis

This vulnerability is classified as CWE-120 (Buffer Copy without Checking Size of Input), a classic buffer overflow condition. The issue resides in the Windows-specific wincred credential helper component of Git, which handles credential storage and retrieval on Windows systems.

The vulnerability requires local access and user interaction to exploit. An attacker who can influence the credential data processed by Git could potentially trigger the buffer overflow condition. The primary security impact is confidentiality-focused, as successful exploitation could lead to unauthorized disclosure of sensitive credential information stored in memory adjacent to the overflowed buffer.

The attack requires that a user interact with a malicious repository or credential source that provides specially crafted input designed to overflow the static target buffer. This could occur when cloning repositories, fetching from remotes, or performing any Git operation that triggers credential helper invocation.

Root Cause

The root cause is improper bounds checking in the wincred credential helper. The helper allocates a fixed-size static buffer named target to store credential key information. When constructing credential identifiers, the code uses wcsncat() to append strings to this buffer without first verifying that sufficient space remains. This oversight allows input data to overflow the buffer boundaries when the combined length exceeds the allocated buffer size.

Attack Vector

The attack vector is local with user interaction required. An attacker must craft a scenario where Git's wincred credential helper processes input that exceeds the expected buffer size. This could be accomplished through:

The vulnerability is exploited when an attacker provides a malicious Git repository URL or credential context with an unexpectedly long hostname, path, or username component. When the wincred helper attempts to construct the credential storage key by concatenating these values into the static target buffer, the lack of bounds checking allows the buffer to overflow. Since the attack scope is marked as "Changed," the overflow can impact memory segments beyond the vulnerable component itself, potentially exposing credentials from other security contexts.

Detection Methods for CVE-2025-48386

Indicators of Compromise

• Monitor for abnormally long repository URLs or credential requests being processed by Git operations
• Check for unexpected crashes or memory access violations in Git credential helper processes
• Look for evidence of credential access patterns that deviate from normal user behavior
• Review authentication logs for unusual repository access following potential exploitation

Detection Strategies

• Deploy application crash monitoring to detect buffer overflow-induced failures in git-credential-wincred.exe
• Implement endpoint detection rules to identify suspicious Git credential helper execution patterns
• Use memory integrity monitoring solutions to detect buffer overflow attempts in real-time
• Monitor Windows Event Logs for Application Error events related to Git credential helper processes

Monitoring Recommendations

• Enable verbose Git logging with GIT_TRACE=1 to capture credential helper invocations
• Configure SentinelOne agents to monitor Git credential helper processes for anomalous behavior
• Implement network monitoring to detect connections to suspicious or unfamiliar Git repositories
• Establish baseline Git usage patterns to identify deviations that may indicate exploitation attempts

How to Mitigate CVE-2025-48386

Immediate Actions Required

• Update Git to the latest patched version immediately: v2.43.7, v2.44.4, v2.45.4, v2.46.4, v2.47.3, v2.48.2, v2.49.1, or v2.50.1
• Consider temporarily switching to an alternative credential helper such as manager or store until patching is complete
• Audit recent Git operations for signs of exploitation, particularly those involving unfamiliar repositories
• Review and rotate any credentials that may have been stored via the wincred helper

Patch Information

The Git project has released security patches addressing this vulnerability across multiple maintained release branches. Users should upgrade to the following versions based on their current release branch:

For complete technical details, refer to the GitHub Security Advisory and the OpenWall OSS Security announcement.

Workarounds

• Configure Git to use an alternative credential helper by running git config --global credential.helper manager or git config --global credential.helper store
• Avoid cloning or fetching from untrusted repositories until the patch is applied
• Implement network-level controls to restrict Git operations to trusted remote hosts only
• Use SSH-based authentication instead of HTTPS with stored credentials where possible

# Switch to Git Credential Manager as an alternative
git config --global credential.helper manager

# Or use the store helper (credentials stored in plaintext file)
git config --global credential.helper store

# Verify current credential helper configuration
git config --global credential.helper