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Vulnerabilities

Security incident · CVE-2026-114096

Dulwich: Symlink write-through in checkout(paths=[]) via raw os.open bypasses all symlink protections

Published Oct 2, 2026 · catalog updated Oct 21, 2026 · Dulwich: Symlink write-through in

Open the advisory

Exploitation likelihood is not on this record for CVE-2026-114096. A missing EPSS score is not a low risk. Compare Dulwich: Symlink write-through in with the linked advisory before you change production.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Dulwich: Symlink write-through in).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
  • EPSS is missing. A missing score is not a low risk.
Severity
High8.6
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
Awaiting synchronization with FIRST
Remediation
Advisory link
Affected products
PyPI dulwich

## Summary Dulwich's code path writes files using raw followed by . This code path does NOT call at all, completely bypassing any symlink protections (including the unreleased d09f8af fix). without follows symlinks at both the target file and intermediate directories, allowing arbitrary file writes. ## Root Cause At , the implementation: (line 601-631) only performs name validation — checking that the path doesn't start with or and that components pass checks. It performs zero filesystem symlink detection. ## Impact An attacker can craft a malicious repository that, when a victim clones it and runs , writes attacker-controlled content (with attacker-controlled permissions) to any filesystem location accessible to the user. Writing to achieves RCE on the next git checkout. ## Attack Scenario 1. Attacker creates a repository where HEAD has as a symlink (mode 120000, content ), and tag has as an executable file (mode 100755, content ) 2. Victim clones the repository — worktree has → (a symlink) 3. Victim runs to restore a specific file from a tag 4. passes — name validation only, no symlink check 5. follows the symlink → opens for writing 6. writes the malicious payload to the hook 7. Next checkout operation triggers the hook → RCE ## Suggested Fix Replace the raw path with a call to (once that function is hardened against intermediate symlinks), or add explicit symlink detection: resolve the path with and verify it stays within the worktree root before opening. Reported by **zx (Jace)**

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • PyPI dulwich0.24.0 → 1.2.8

How to fix CVE-2026-114096

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

Exploitation likelihood is not on this record for CVE-2026-114096. A missing EPSS score is not a low risk. Compare Dulwich: Symlink write-through in with the linked advisory before you change production.

Which versions are affected?

Compare what you have installed with 0.24.0 → 1.2.8. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-59: Link Following; CWE-61. EPSS is not on this record yet. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 2, 2026 · GitHub Advisory Database

    Detected

    ## Summary Dulwich's code path writes files using raw followed by . This code path does NOT call at all, completely bypassing any symlink protections (including the unreleased d09f8af fix). without follows symlinks at both the target file and intermediate directories, allowing arbitrary file writes. ## Root Cause At , the implementation: (line 601-631) only performs name validation — checking that

  2. Oct 21, 2026 · GitHub Advisory Database

    Fix available

    dulwich fixed in 1.2.8

  3. Oct 21, 2026 · GitHub Advisory Database

    Fix available

    dulwich fixed in 1.2.8

  4. Oct 21, 2026 · GitHub Advisory Database

    Updated

    ## Summary Dulwich's code path writes files using raw followed by . This code path does NOT call at all, completely bypassing any symlink protections (including the unreleased d09f8af fix). without follows symlinks at both the target file and intermediate directories, allowing arbitrary file writes. ## Root Cause At , the implementation: (line 601-631) only performs name validation — checking that

Sources

References

Freshness

Last verified in this catalog Oct 21, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.