CVE-2026-42305: Conda lock · Dulwich has an arbitrary file write via NTFS-hostile tree entries on Windows
Affects conda-lockSource GCVE Database
Not known to be exploited · CVSS 8.8 High : upgrade to 4.0.5 soon.
Data as of 4 Nov 2026, 20:35 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.0.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.
What to do
Upgrade conda-lock to 4.0.5.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewconda-lockpkg:brew/conda-lockOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in Dulwich 1.2.5 and conda-lock 4.0.5. Users should upgrade to these versions or later. There is no effective pre-patch workaround because the core.protectNTFS configuration key was silently ignored on affected versions. Users unable to upgrade should avoid cloning, fetching, or checking out untrusted repositories with Dulwich on Windows. After upgrading, no additional configuration is required as the NTFS validator is enabled by default on all platforms.
Description
CVE-2026-42305 is a high-severity vulnerability in Dulwich used by conda-lock on Windows that allows arbitrary file write and remote code execution when cloning or checking out a malicious Git repository. The flaw arises from Dulwich's path-element validator accepting filenames containing bytes interpreted by Windows as path syntax, enabling attackers to plant files inside the victim's .git directory or escape the working tree. This can lead to execution of malicious Git hooks. The issue is fixed in Dulwich 1.2.5 and conda-lock 4.0.5. No effective workaround exists other than upgrading or avoiding untrusted repositories on Windows.
References
- github.com/jelmer/dulwich/security/advisories/GHSA-897w-fcg9-f6xj (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-42305 (opens in a new tab)
- github.com/jelmer/dulwich/commit/49eb56e51aad637fc23d54bf2a08cb42739b8290 (opens in a new tab)
- github.com/jelmer/dulwich/commit/57efc4aa1581e038915a0fd79365be53b150f4a9 (opens in a new tab)
- github.com/jelmer/dulwich (opens in a new tab)
- github.com/jelmer/dulwich/releases/tag/dulwich-1.2.5 (opens in a new tab)