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 severity · published Mar 3, 2021

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`

4.8

CVSS

1.1%

EPSS

On KEV

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 vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Attack vector

Network

Complexity

Low

Privileges

High

User interaction

Required

Confidentiality

Low

Integrity

Low

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)1.1% · higher than 64% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

Fedora · Fedoraproject

34 · source: NVD

Nextcloud Server · Nextcloud

before 20.0.6 · source: NVD

Affected product

Fedora

Fedoraproject

All Fedora CVEs

References

NVD

https://nvd.nist.gov/vuln/detail/CVE-2021-22878

CVE.org

https://www.cve.org/CVERecord?id=CVE-2021-22878

Patch

https://github.com/nextcloud/server/pull/25234

Exploit

https://hackerone.com/reports/896522

lists.fedoraproject.org

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L6BO6P6MP2MOWA6PZRXX32PLWPXN5O4S/

Vendor Advisory

https://nextcloud.com/security/advisory/?id=NC-SA-2021-005