CVE-2026-54221

MEDIUM
MEDIUM Priority: 0.01 BB Relevance: 60/100
Published: 2026-06-18 Modified: 2026-10-26 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: Active
S: X
AT: None
VC: None
VI: None
VA: None

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.

Weakness Classification (1)

Bug Bounty Relevance

60 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

5.1 / 10.0 v4.0
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.29%
Raw Score 0.002930
Percentile 21.8%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00293
2026-10-28
0.00293

Intelligence Sources

nvd ref →