CVE-2026-55424 PUBLISHED

Discourse: Topic featured link susceptible to stored XSS

Assigner: GitHub_M
Reserved: 16.06.2026 Published: 09.07.2026 Updated: 10.07.2026

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.

Metrics

CVSS 4.0

CVSS 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
CVSS Score: 7.4

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	Low
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	discourse
Product	discourse
Versions	Version >= 2026.1.0-latest, < 2026.1.5 is affected Version >= 2026.4.0-latest, < 2026.4.2 is affected Version >= 2026.5.0-latest, < 2026.5.1 is affected

References

Problem Types

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE