Low severity · published Sep 21, 2026
CVE-2026-77166
The emoji field in the page emoji update endpoint does not properly validate user input
2.4
CVSS
0.3%
EPSS
No
On KEV
Description
The emoji field in the page emoji update endpoint does not properly validate user input. By injecting long text and line breaks, the sidebar layout becomes broken and can hide other items.
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
Required
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
Collectives · Nextcloud
3.2.1 through 3.5.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77166
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-77166
hackerone.com
https://hackerone.com/reports/3599470
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