Buffer overflow in Git-For-Windows Git

CVE-2026-100408

Git for Windows is the Windows port of Git. From 2.43.0.windows.1 until 2.55.0.windows.3, when a matching git:* credential exists in Windows Credential Manager and a git-credential-wincred erase input includes a password field, the operation in contrib/credential/wincred/git-credential-wincred.c allocates a buffer of exactly CredentialBlobSize bytes in match_cred_password() and then uses wcsncpy_s() to copy the corresponding number of wide characters plus a terminating NUL. The destination capacity is also supplied in bytes instead of WCHAR elements, allowing a fixed two-byte NUL write past the allocation before the password comparison determines whether CredDeleteW() should remove the credential; erase without a password field does not enter this comparison path. The helper can terminate with Windows heap-corruption status, and git credential reject can appear successful while the rejected credential remains stored. This issue is fixed in version 2.55.0.windows.3.

Vulnerability class: Buffer Overflow

Published .

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-100408?
CVE-2026-100408 is a medium-severity vulnerability in Git-For-Windows Git, classified under Out-of-bounds Write. CVSS score: 4.4/10. Published 2026-11-04.
How severe is CVE-2026-100408?
Medium severity. CVSS v3 base score is 4.4 out of 10.