XSS in Znuny

CVE-2026-77506

Znuny before LTS 6.5.22 allows AgentTicketEmailResend template XSS.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

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: 0.002 (14.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-77506: held from 0.003 to 0.002.

EPSS over last 30 days · oldest: 0.003 · newest: 0.002 · change: -0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-77506?
CVE-2026-77506 is a medium-severity vulnerability in Znuny, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2026-08-20.
How severe is CVE-2026-77506?
Medium severity. CVSS v3 base score is 4.8 out of 10.