GO-2026-5203Published

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

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-42275

Published

zrok is software for sharing web services, files, and network resources. Prior to version 2.0.2, 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. This issue has been patched in version 2.0.2.

Source published: 8 May 2026 03:45:57 UTC
Source modified: 8 May 2026 12:13:21 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

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

euvd · EUVD-2026-28511

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: May 8, 2026, 3:45:57 AM

dateUpdated: May 8, 2026, 12:13:21 PM

Source published: May 8, 2026, 3:45:57 AM (timezone not stated)
Source modified: May 8, 2026, 12:13:21 PM (timezone not stated)
Observed here: 1 Nov 2026 07:12:48 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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

nvd · CVE-2026-42275

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-22 · CWE-61

Original publisher date fields

published: 2026-05-08T04:16:22.823

lastModified: 2026-10-26T20:10:00.160

1 source CPE criteria · context only

cpe:2.3:a:netfoundry:zrok:*:*:*:*:*:*:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 8 May 2026 04:16:22 UTC
Source modified: 26 Oct 2026 20:10:00 UTC
Observed here: 27 Oct 2026 11:12:01 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 8.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

osv · GHSA-74m3-9qvm-rp9h

Published

**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 interaction. - Scope: Changed — the vulnerability allows an attacker to escape the WebDAV root (the security boundary) and access the broader host filesystem. - Confidentiality Impact: High — arbitrary files readable by the zrok process can be retrieved. - Integrity Impact: High — the WebDAV PUT handler opens files with O_RDWR|O_CREATE|O_TRUNC, meaning symlink targets outside DriveRoot can be overwritten (e.g. ~/.ssh/authorized_keys). - Availability Impact: None — no direct availability impact. Affected Components - drives/davServer/file.go — Dir.OpenFile (line 140), Dir.Stat (line 176), Dir.Mkdir (line 133), Dir.RemoveAll (line 151) - endpoints/drive/backend.go — NewBackend (line 51–52)

Source published: 25 Apr 2026 23:34:35 UTC
Source modified: 25 Jun 2026 19:56:16 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Publisher rating · HIGH

osv · GO-2026-5203

Published

zrok: WebDAV drive backend follows symlinks outside DriveRoot, enabling host filesystem read/write in github.com/openziti/zrok

Source published: 25 Jun 2026 18:43:15 UTC
Source modified: 25 Jun 2026 19:45:16 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.