{"id":"CVE-2026-42275","aliases":["GHSA-74m3-9qvm-rp9h","GO-2026-5203"],"url":"https://o3.security/vulnerability/CVE-2026-42275","summary":"zrok: WebDAV drive backend follows symlinks outside DriveRoot, enabling host filesystem read/write","details":"**Summary**\nThe 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.\n\n- Attack Vector: Network — exploitation is performed entirely over the WebDAV endpoint; the attacker issues HTTP requests to the public zrok share URL.\n- 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).\n- Privileges Required: None — zrok share public --backend-mode drive exposes the WebDAV endpoint with no authentication by default.\n- User Interaction: None — once the symlink precondition is met, exploitation requires no user interaction.\n- Scope: Changed — the vulnerability allows an attacker to escape the WebDAV root (the security boundary) and access the broader host filesystem.\n- Confidentiality Impact: High — arbitrary files readable by the zrok process can be retrieved.\n- 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).\n- Availability Impact: None — no direct availability impact.\n\nAffected Components\n\n- drives/davServer/file.go — Dir.OpenFile (line 140), Dir.Stat (line 176), Dir.Mkdir (line 133), Dir.RemoveAll (line 151)\n- endpoints/drive/backend.go — NewBackend (line 51–52)","published":"2026-05-08T03:45:57.209Z","modified":"2026-08-12T03:51:20.458292731Z","cvss":{"score":8.7,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N"},"epss":{"score":0.0033,"percentile":0.25757,"asOf":"2026-08-14"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/openziti/zrok","fixedVersion":null},{"ecosystem":"Go","name":"github.com/openziti/zrok/v2","fixedVersion":"2.0.2"}],"fix":{"url":"https://github.com/openziti/zrok/commit/459bcfc1e121decae1b1d11c37ad94e4ed5bbf2e","label":"openziti/zrok@459bcfc"},"references":[{"type":"WEB","url":"https://github.com/openziti/zrok/releases/tag/v2.0.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42275.json"},{"type":"ADVISORY","url":"https://github.com/openziti/zrok/security/advisories/GHSA-74m3-9qvm-rp9h"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42275"},{"type":"FIX","url":"https://github.com/openziti/zrok/commit/459bcfc1e121decae1b1d11c37ad94e4ed5bbf2e"},{"type":"PACKAGE","url":"https://github.com/openziti/zrok"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:20.458292731Z"}}