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VulnerabilityPublished Updated

CVE-2026-42305: Conda lock · Dulwich has an arbitrary file write via NTFS-hostile tree entries on Windows

Affects conda-lockSource GCVE Database

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Authoritative record:CVE-2026-42305· High 8.8

Not known to be exploited · CVSS 8.8 High : upgrade to 4.0.5 soon.

Data as of 4 Nov 2026, 20:35 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Homebrewconda-lockpkg:brew/conda-lockOther threatsAffected
  • >=3.0.0 <4.0.5
Fixed in
  • 4.0.5

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

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