Vulnerability · Published Jun 18, 2026 · Assigned by CERT-PL

CVE-2026-54221Reflected XSS in UBB.threads

Medium 5.1

In plain English

A medium-severity cross-site scripting in UBB.threads from UBB Systems. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 4.0)5.1Medium

Exploit odds (30 days)0.3%top 78.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

UBB.threads is vulnerable to Reflected XSS. The application improperly handles user input in certain requests, enabling attackers to execute arbitrary JavaScript in the context of a victim's browser by tricking them into clicking a crafted link. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 7.7.5 but may also affect other versions.

Affected products (as reported)

Vendor	Product	Versions
UBB Systems	UBB.threads	0 – through 7.7.5

Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References

https://www.ubbcentral.com/ product
https://cert.pl/en/posts/2026/06/CVE-2026-54219 third-party-advisory