Reflected XSS the login page through the 'username' parameter

published 2026-04-07 7 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-19849

cvss: 8.1; version 3.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits: 0; none known

ChurchCRM is an open-source church management system. Prior to 7.1.0, there is a Reflected Cross-Site Scripting (XSS) vulnerability on the login page, which is caused by the lack of sanitization or encoding of the username parameter received from the URL. The username parameter value is directly displayed in the login page input element without filter, allowing attackers to insert malicious JavaScript scripts. If successful, script can be executed on the client side, potentially stealing sensitive data such as session cookies or replacing the display to show the attacker's login form. This vulnerability is fixed in 7.1.0.

Patch / fix

fixed in 1

churchcrm churchcrm 7.1.0

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 7 mo ago (2026-04-08)

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/ChurchCRM/CRM/security/advisories/GHSA-rx8c-j7x8-w3hj referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.0	8.1	CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Affected products

ChurchCRM CRM

Classification

Weakness

CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page
CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /ChurchCRM/CRM/security/advisories/GHSA-rx8c-j7x8-w3hj
exploit, third-party-advisory

Sources

CVE List CVE-2026-39344
NVD CVE-2026-39344

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary