Log in Start free

Vulnerability · Published Jul 9, 2026 · Assigned by GitHub_M

CVE-2026-55424Discourse: Topic featured link susceptible to stored XSS

High 7.4

In plain English

A high-severity cross-site scripting in discourse from discourse. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).

Severity (CVSS 4.0)7.4High
Exploit odds (30 days)0.4%top 64.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

VendorProductVersions
discourse discourse >= 2026.1.0-latest, < 2026.1.5>= 2026.4.0-latest, < 2026.4.2>= 2026.5.0-latest, < 2026.5.1

Weakness: CWE-79 · Vector: 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

References