CVE-2026-55424
Discourse: Topic featured link susceptible to stored XSS
EPSS 0.27%
Description
Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, a topic "featured link" was not sufficiently normalized and escaped before being rendered in the topic list, allowing a user who can set a featured link to inject JavaScript when default Content Security Policy protections were modified or disabled. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
How to fix CVE-2026-55424
To remediate CVE-2026-55424, upgrade the affected package to a fixed version below.
- —upgrade to 2026.1.5 or later
Is CVE-2026-55424 being exploited?
Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 2026.1.0, < 2026.1.5, >= 2026.4.0, < 2026.4.2, >= 2026.5.0, < 2026.5.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/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 |