Vulnerability · Published Oct 27, 2026 · Assigned by hackerone

CVE-2026-87897

Medium 4.6

In plain English

A medium-severity server-side request forgery in whiteboard from Nextcloud. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities).

Severity (CVSS 3.0)4.6Medium

Exploit odds (30 days)0.2%top 89.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
Nextcloud	whiteboard	1.0.0 – before 1.0.0

Weakness: CWE-918 · Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

References

https://hackerone.com/reports/3576823