CVE-2026-55424
Discourse: Topic featured link susceptible to stored XSS
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.
INFO
Published Date :
July 9, 2026, 10:17 p.m.
Last Modified :
July 14, 2026, 1:26 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Discourse to version 2026.6.0 or later.
- Ensure Content Security Policy is properly configured.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55424.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55424 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55424
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55424 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55424 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* versions from (including) 2026.1.0 up to (excluding) 2026.1.5 *cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* versions from (including) 2026.4.0 up to (excluding) 2026.4.2 *cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* versions from (including) 2026.5.0 up to (excluding) 2026.5.1 *cpe:2.3:a:discourse:discourse:2026.6.0:*:*:*:latest:*:*:* Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/commit/1bce8881e4253d9bbab56f011a12ef899b926b59 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/commit/6679d9a5083488bae10c2adbb345c481c583242c Types: Patch Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/commit/6828aee9b15c2655d63b515ac919830bd540ff83 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/commit/c9b9405f5bd0bf0269e505e28e3aad388d7657c5 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/releases/tag/v2026.1.5 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/releases/tag/v2026.4.2 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/releases/tag/v2026.5.1 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/releases/tag/v2026.6.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/discourse/discourse/security/advisories/GHSA-695w-7fv8-mxg3 Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 10, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-55424', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-10T14:39:57.512653Z'} -
New CVE Received by [email protected]
Jul. 09, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'discourse', 'product': 'discourse', 'versions': [{'status': 'affected', 'version': '>= 2026.1.0-latest, < 2026.1.5'}, {'status': 'affected', 'version': '>= 2026.4.0-latest, < 2026.4.2'}, {'status': 'affected', 'version': '>= 2026.5.0-latest, < 2026.5.1'}]}] Added 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. Added CVSS V4.0 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 Added CWE CWE-79 Added Reference https://github.com/discourse/discourse/commit/1bce8881e4253d9bbab56f011a12ef899b926b59 Added Reference https://github.com/discourse/discourse/commit/6679d9a5083488bae10c2adbb345c481c583242c Added Reference https://github.com/discourse/discourse/commit/6828aee9b15c2655d63b515ac919830bd540ff83 Added Reference https://github.com/discourse/discourse/commit/c9b9405f5bd0bf0269e505e28e3aad388d7657c5 Added Reference https://github.com/discourse/discourse/releases/tag/v2026.1.5 Added Reference https://github.com/discourse/discourse/releases/tag/v2026.4.2 Added Reference https://github.com/discourse/discourse/releases/tag/v2026.5.1 Added Reference https://github.com/discourse/discourse/releases/tag/v2026.6.0 Added Reference https://github.com/discourse/discourse/security/advisories/GHSA-695w-7fv8-mxg3