What is CVE-2021-21494?

CVE-2021-21494 is a medium-severity vulnerability in Mk-Auth, classified under Incorrect Permission Assignment for Critical Resource. CVSS score: 4.8/10. Published 2021-01-04.

How severe is CVE-2021-21494?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Vulnerability in Mk-Auth

CVE-2021-21494

MK-AUTH through 19.01 K4.9 allows XSS via the admin/logs_ajax.php tipo parameter. An attacker can leverage this to read the centralmka2 (session token) cookie, which is not set to HTTPOnly.

Published 2021-01-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (41.8th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 41.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

Mk-Auth

Weakness classification (CWE)

CWE-732 — Incorrect Permission Assignment for Critical Resource

References

mk-auth.com.br/ (Vendor Advisory)
gist.github.com/alacerda/380b8923e36a29a02ba1457c1eb3ec2f (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21494?: CVE-2021-21494 is a medium-severity vulnerability in Mk-Auth, classified under Incorrect Permission Assignment for Critical Resource. CVSS score: 4.8/10. Published 2021-01-04.
How severe is CVE-2021-21494?: Medium severity. CVSS v3 base score is 4.8 out of 10.