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TI-2026-81402 Aliases CVE-2026-87897

Server-side request forgery in Nextcloud Whiteboard leaks user tokens

Priority LOW 21CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.0 · CNA. Fix status from CNA.

Summary

The Nextcloud Whiteboard app is affected. A server-side request forgery flaw (CWE-918) lets the app reach internal Chrome DevTools Protocol APIs. A low-privileged attacker can repeatedly leak the JWT authentication token of another user when that user starts a recording, which gives the attacker read and write access to the victim's whiteboard. User interaction is required.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00203 10th percentileScored 2026-11-07
Fix Fixed whiteboard (Nextcloud): 1.0.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nextcloudwhiteboard1.0.0 to before 1.0.01.0.0Patch availableCNA
  • whiteboard Vendornextcloud Affected 1.0.0 to before 1.0.0 Fixed in 1.0.0 Patch available CNA

Remediation

Upgrade Nextcloud Whiteboard to version 1.0.0, which fixes the issue.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

  • Fix · CNA whiteboard (Nextcloud) Fixed in 1.0.0

Timeline

  1. 2026-10-27 Threatist record created from CVE-2026-87897
  2. 2026-11-04 CISA SSVC decision points changed

References

Other 1

  • TI-2026-18211 Windmill < 1.615.0 Operator Role Missing Authorization Checks RCE CVSS 4.0HIGH 8.7
  • TI-2023-14838 NextCloud Cookbook's pull-checks.yml workflow is vulnerable to OS Command Injection CVSS 3.1HIGH 8.8
  • TI-2022-08650 Command Injection in Appointment Emails for Nextcloud Calendar CVSS 3.1CRITICAL 9.8
  • TI-2023-20855 Users can delete external storage mount points CVSS 3.1HIGH 7.7
  • TI-2023-11091 Nextcloud download permissions can be changed by resharer CVSS 3.1HIGH 7.5
  • TI-2023-10624 Nextcloud Server vulnerable to SSRF via filter bypass due to lax checking on IPs CVSS 3.1MEDIUM 5.3
See all 401 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences