Vulnerability Report

CVE-2026-55424

Title: Stored XSS via featured link in Discourse

XSS

Proof Of Concept

No public PoC currently indexed for CVE-2026-55424.

CWE Category CWE-79
Published Date Jul 09, 2026
Modified Date Jul 14, 2026
Exploit Status Not Found
Score 7.4 CVSS v4.0
Exploit Probability (EPSS)
0.27%

Vulnerability Summary

CVE-2026-55424: 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.

Impacted Vendors

D
discourse 1

Reference Links

https://github.com/discourse/discourse/commit/1bce8881e4253d9bbab56f011a12ef899b926b59 https://github.com/discourse/discourse/commit/6679d9a5083488bae10c2adbb345c481c583242c https://github.com/discourse/discourse/commit/6828aee9b15c2655d63b515ac919830bd540ff83 https://github.com/discourse/discourse/commit/c9b9405f5bd0bf0269e505e28e3aad388d7657c5 https://github.com/discourse/discourse/releases/tag/v2026.1.5 https://github.com/discourse/discourse/releases/tag/v2026.4.2 https://github.com/discourse/discourse/releases/tag/v2026.5.1 https://github.com/discourse/discourse/releases/tag/v2026.6.0 https://github.com/discourse/discourse/security/advisories/GHSA-695w-7fv8-mxg3
CVSS v4.0
Source Entity [email protected]
Severity HIGH
7.4
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
PASSIVE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
N/A
RAW 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/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
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
5.4
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-55424 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction PASSIVE
CVSS Vector String 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

Affected Stack

No specific products linked.