CVE-2026-100407: Memory Corruption (CVSS 4.4)

Description

Git for Windows is the Windows port of Git. From 2.44.0.windows.1 until 2.55.0.windows.3, the git-credential-wincred store operation in contrib/credential/wincred/git-credential-wincred.c uses _scwprintf() to size a formatted wide-character credential buffer without space for the terminating NUL when both password and oauth_refresh_token are present. The operation also passes a byte count to _snwprintf_s() where a wide-character count is required, allowing the terminator to be written one WCHAR past the heap allocation before CredWriteW() persists the credential. The resulting fixed two-byte NUL overwrite can terminate the helper with Windows heap-corruption status and can cause git credential approve to report success even though the OAuth credential was not stored. This issue is fixed in version 2.55.0.windows.3.

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CVSS v3.1 Score

4.4

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

EPSS — Exploit Prediction

0.0012

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

References

Other References

https://github.com/git-for-windows/git/commit/52ca1113d651127f89477a8763f86ab20f645e1d https://github.com/git-for-windows/git/releases/tag/v2.55.0.windows.3 https://github.com/git-for-windows/git/security/advisories/GHSA-v3h4-vrpr-rh9x

Frequently Asked Questions

What is CVE-2026-100407? +

Git for Windows is the Windows port of Git. From 2.44.0.windows.1 until 2.55.0.windows.3, the git-credential-wincred store operation in contrib/credential/wincred/git-credential-wincred.c uses _scwprintf() to size a formatted wide-character credential buffer without space for the terminating NUL when both password and oauth_refresh_token are present. The operation also passes a byte count to _snwprintf_s() where a wide-character count is required, allowing the terminator to be written one WCHAR past the heap allocation before CredWriteW() persists the credential. The resulting fixed two-byte NUL overwrite can terminate the helper with Windows heap-corruption status and can cause git credential approve to report success even though the OAuth credential was not stored. This issue is fixed in version 2.55.0.windows.3. It has a CVSS v3.1 base score of 4.4 (MEDIUM).

How severe is CVE-2026-100407? +

CVE-2026-100407 has a CVSS v3.1 score of 4.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0012, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-100407? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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