zrok: WebDAV drive backend follows symlinks outside DriveRoot, enabling host filesystem read/write

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

EPSS

• CVE-2026-42275: 0.33% estimated exploitation activity in the next 30 days; percentile 26.19 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The zrok WebDAV drive backend (davServer.Dir) restricts path traversal through lexical normalization but does not prevent symlink following. When a symbolic link inside the shared DriveRoot points to a location outside that root, remote WebDAV consumers can read files and—on shares without OS-level permission restrictions—write or overwrite files anywhere on the host filesystem accessible to the zrok process. - Attack Vector: Network — exploitation is performed entirely over the WebDAV endpoint; the attacker issues HTTP requests to the public zrok share URL. - Attack Complexity: High — a precondition outside the attacker's direct control must hold: a symlink pointing outside DriveRoot must already exist within it (created locally, not via WebDAV). - Privileges Required: None — zrok share public --backend-mode drive exposes the WebDAV endpoint with no authentication by default. - User Interaction: None — once the symlink precondition is met, exploitation requires no user…

Published by the source

25 Apr 2026, 23:34 UTC

Last modified by the source

12 May 2026, 13:29 UTC

Source last checked

26 Oct 2026, 15:20 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-74m3-9qvm-rp9h

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# Patch Next advisory brief: CVE-2026-42275

Advisory: zrok: WebDAV drive backend follows symlinks outside DriveRoot, enabling host filesystem read/write
IDs: CVE-2026-42275, GHSA-74m3-9qvm-rp9h
Record: https://patchnext.com/advisories/cve-2026-42275 (revision 1, source checked 26 Oct 2026, 15:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: github.com/openziti/zrok/v2 2.0.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/openziti/zrok: affected <= 1.1.11
- Go github.com/openziti/zrok/v2: affected < 2.0.2; fixed in 2.0.2

## Suggested inspection (read-only)
- Go github.com/openziti/zrok: check the installed version with your package manager.
- Go github.com/openziti/zrok/v2: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/openziti/zrok, github.com/openziti/zrok/v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-74m3-9qvm-rp9h (GitHub-reviewed advisory GHSA-74m3-9qvm-rp9h lists affected ranges: Go github.com/openziti/zrok >=0 =0 <2.0.2)

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