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

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.

7.4 HIGHEPSS 0.41%Not in KEVNVD: Analyzed

Last updated: 2026-07-14 01:26 UTC

OverviewCVSS details

7.4HIGHCVSS 4.0

Score source: GitHub_M (CNA)
NVD status: Analyzed
Published: Jul 9, 2026
Assigner: GitHub_M

Affected

discourse (discourse)

Versions: >= 2026.1.0-latest, < 2026.1.5 · >= 2026.4.0-latest, < 2026.4.2

All affected versions →

Exploitation

Public exploit: None listed
CISA KEV: Not listed
KEV due date: —
SSVC: Exploitation none · Automatable no · Impact total

EPSS · FIRST, scored Nov 7

0.41%chance of exploitation in 30 days

Higher than 36.04% of CVEs

CVSS 4.0 · GitHub_M (CNA)

7.4High

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

Attack vector: Network
Attack complexity: Low
Attack requirements: Present
Privileges required: Low
User interaction: Passive
Confidentiality impact: High
Integrity impact: High
Availability impact: None
Confidentiality (other systems): None
Integrity (other systems): None
Availability (other systems): None

CVSS 3.1 · NVD

5.4Medium

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: Required
Scope: Changed
Confidentiality impact: Low
Integrity impact: Low
Availability impact: None

NVD status: Analyzed

Overview Affected Products References

NVD CVE.org

Overview

Severity

Score	Severity	Version	Vector String
7.4	HIGH	4.0GitHub_M (CNA)	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
5.4	MEDIUM	3.1NVD	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Details

CVE ID: CVE-2026-55424
Status: Analyzed
Assigner (CNA): GitHub_M
Published: Jul 9, 2026
Last modified: 2026-07-14 01:26 UTC
Weaknesses: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Sources

Refreshed hourly from the sources above. Last fetched 2026-11-08 08:16 UTC.