VulnerabilityModified
CVE-2021-22878
Nextcloud Server prior to 20.0.6 is vulnerable to reflected cross-site scripting (XSS) due to lack of sanitization in `OC.Notification.show`.
MEDIUM 4.8EPSS 1.06%
Does this matter?
Lower severity and a low EPSS score (1.06%). Track it; it rarely justifies an emergency change on its own.
Description
Nextcloud Server prior to 20.0.6 is vulnerable to reflected cross-site scripting (XSS) due to lack of sanitization in `OC.Notification.show`.
- CVSS 3.1
- 4.8 MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 1.06% probability · 64th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Affected
- nextcloud/nextcloud server · fedoraproject/fedora
- Source
- support@hackerone.com
EPSS 1.1% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/nextcloud/server/pull/25234Patch, Third Party Advisory
- https://hackerone.com/reports/896522Exploit, Issue Tracking, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L6BO6P6MP2MOWA6PZRXX32PLWPXN5O4S/
- https://nextcloud.com/security/advisory/?id=NC-SA-2021-005Vendor Advisory
- https://github.com/nextcloud/server/pull/25234Patch, Third Party Advisory
- https://hackerone.com/reports/896522Exploit, Issue Tracking, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L6BO6P6MP2MOWA6PZRXX32PLWPXN5O4S/
- https://nextcloud.com/security/advisory/?id=NC-SA-2021-005Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.