GHSA-897w-fcg9-f6xj · Severity: high · Ecosystem: pip — Dulwich has an arbitrary file write via NTFS-hostile tree entries on Windows
Dulwich is a pure-Python implementation of the Git file formats and protocols. Versions starting with 0.10.0 and prior to 1.2.5 have an arbitrary file write leading to remote code execution when cloning or checking out a malicious Git repository on Windows. Dulwich's path-element validator accepted tree entries whose filenames contained bytes that Windows interprets as structural path syntax. Contributing configuration bugs made matters worse. The core.protectNTFS and core.protectHFS settings were looked up under a wrong option name and so user-set values were silently ignored, and core.protectNTFS only defaulted to true on Windows (Git upstream has defaulted it to true everywhere since CVE-2019-1353). Both have been corrected. Anyone who clones, fetches, or checks out an untrusted repository with Dulwich on Windows - either through the Dulwich CLI, porcelain.clone, or any downstream tool built on Dulwich - is impacted. POSIX clones are not directly exploitable (on POSIX \ is a literal filename byte), but a POSIX user can unknowingly propagate a malicious tree to Windows consumers via push or re-publication. This issue is fixed in Dulwich 1.2.5. Users should upgrade to 1.2.5 or later. There is no effective pre-patch workaround. On affected versions the core.protectNTFS configuration key was silently ignored, so setting it to true does not mitigate the issue. Users who cannot upgrade should avoid cloning, fetching, or checking out untrusted repositories with Dulwich on Windows. After upgrading the NTFS validator is on by default on every platform, so no additional configuration is required.
Conclusion & alert: CVE-2026-42305 is rated Moderate Risk (54.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.85%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.22% | 0.85% | +0.63% |
| 2 | 2026-06-11 | — | 0.22% | — |
Full EPSS history (2 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 8.8 | 3.1 | HIGH |
|
2.8 | 5.9 | [email protected] |
GHSA-897w-fcg9-f6xj · Severity: high · Ecosystem: pip — Dulwich has an arbitrary file write via NTFS-hostile tree entries on Windows
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
unimportant | CVE-2026-42305 unimportant priority: Debian including 1 source packages (dulwich), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2026-42305 |
suse
|
medium | CVE-2026-42305 severity moderate: SUSE including 3 source package names (python311-dulwich-1.2.5-1.1, python313-dulwich-1.2.5-1.1, python314-dulwich-1.2.5-1.1), 3 product×package rows across 1 product lines (openSUSE Tumbleweed): Fixed 3. | https://www.suse.com/security/cve/CVE-2026-42305/ |
ubuntu
|
medium | CVE-2026-42305 medium priority: Ubuntu including 1 source packages (dulwich), 7 status rows across 7 suites (bionic, focal, jammy, noble, questing, resolute, upstream): needs-triage 6, released 1. | https://ubuntu.com/security/CVE-2026-42305 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| No affected products in dataset. | |||