Vulnerability in Nextcloud whiteboard

[ Description ]Official description

A SSRF vulnerability found that enables access to internal Chrome Devtools Protocol APIs that can leak the JWT authentication token for another user. A low privileged attacker could continually exploit this vulnerability to leak the JWT authentication token for another user when they start a recording, which then enables the attacker read/write access to the victim's Whiteboard.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund26 Oct 2026WID-SEC-2026-4185

  Nextcloud (Server, Tables, Whiteboard, Files Confidential, Collectives, Richdocuments): Multiple vulnerabilities Translated from German

  CVE-2026-77171CVE-2026-82986CVE-2026-77167+7 more CVEs

[ References ]References

• hackerone.com/reports/3576823