Git for Windows: git-credential-wincred Erase Path Heap Overflow
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 2.55.0.windows.3
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 2.55.0.windows.3.
- Exploitation?/40Exploitation: unknown (data gap). No CISA SSVC exploitation rating yet
- Exposure?/25Exposure: unknown (data gap). No advisory context yet
- Reach?/20Reach: unknown (data gap). No tracked technology or package matched
- Severity4.4/10CVSS 4.4
- No patch0/5No signal
What would change the score
- Would score about 59 if added to CISA KEV
- Would score about 54 if CISA's SSVC rates exploitation active
- Would score about 26 if advisories confirm default setups are exposed
CVE-2026-100408 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 4.4 (medium) and affects git; fixed in 2.55.0.windows.3.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 4/100 · provisional
- Fix
- Fixed in 2.55.0.windows.3
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Git for Windows' git-credential-wincred helper has a heap buffer overflow when erasing a stored git credential that includes a password, which a local attacker can trigger with no login but requires user interaction. The overflow can crash the helper and leave a credential stored even though `git credential reject` reports success.
Read the original description
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.
What to do
Upgrade to a fixed version: 2.55.0.windows.3.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- git-for-windows git
From 2.43.0.windows.1 · fixed in 2.55.0.windows.3
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-100408
Is CVE-2026-100408 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-100408?
git: from 2.43.0.windows.1 before 2.55.0.windows.3.Source: cve.now feed data
How do I fix CVE-2026-100408?
Upgrade to a fixed version: 2.55.0.windows.3.Source: cve.now feed data