What is CVE-2021-25977?

CVE-2021-25977 is a medium-severity vulnerability in Dotnetfoundation Piranha Cms, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-10-25.

How severe is CVE-2021-25977?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Dotnetfoundation Piranha Cms

CVE-2021-25977

In PiranhaCMS, versions 7.0.0 to 9.1.1 are vulnerable to stored XSS due to the page title improperly sanitized. By creating a page with a specially crafted page title, a low privileged user can trigger arbitrary JavaScript execution.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-10-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (49.2th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Dotnetfoundation Piranha Cms
Piranhacms Piranha — versions 7.0.0, unspecified

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/PiranhaCMS/piranha.core/commit/543bc53c7dbd28c793ec960b57fb0e716c6b1… (Patch, Third Party Advisory)
www.whitesourcesoftware.com/vulnerability-database/CVE-2021-25977 (Third Party Advisory)

Frequently asked questions

What is CVE-2021-25977?: CVE-2021-25977 is a medium-severity vulnerability in Dotnetfoundation Piranha Cms, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-10-25.
How severe is CVE-2021-25977?: Medium severity. CVSS v3 base score is 5.4 out of 10.