What is CVE-2026-26378?

CVE-2026-26378 is a medium-severity vulnerability in Koha, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-06-03.

How severe is CVE-2026-26378?

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

XSS in Koha

CVE-2026-26378

Cross Site Scripting vulnerability in Koha 25.11 and before allows a remote attacker to execute arbitrary code via file upload function in Invoice features

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.001 (16.1th percentile) — read the EPSS interpretation.

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.

Affected products

Koha
N/a — versions n/a

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

cve@mitre.org (Product)
cve@mitre.org (Third Party Advisory)
cve@mitre.org (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2026-26378?: CVE-2026-26378 is a medium-severity vulnerability in Koha, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-06-03.
How severe is CVE-2026-26378?: Medium severity. CVSS v3 base score is 5.4 out of 10.