What is CVE-2021-26799?

CVE-2021-26799 is a medium-severity vulnerability in Omeka, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-07-23.

How severe is CVE-2021-26799?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Omeka

CVE-2021-26799

Cross Site Scripting (XSS) vulnerability in admin/files/edit in Omeka Classic <=2.7 allows remote attackers to inject arbitrary web script or HTML.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-07-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.010 (62.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 62.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Omeka

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/omeka/Omeka/issues/935 (Exploit, Third Party Advisory)
github.com/omeka/Omeka/commit/08bfdf470e234edb68e5307a2fef8c899d89256c (Exploit, Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-26799?: CVE-2021-26799 is a medium-severity vulnerability in Omeka, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-07-23.
How severe is CVE-2021-26799?: Medium severity. CVSS v3 base score is 6.1 out of 10.