CVE-2026-55420
Discourse: Remote code execution via pdf uploads
Description
Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, under certain non-default configurations, processing of PDF uploads could be exploited to obtain RCE on the server. This issue is patched in 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
INFO
Published Date :
July 9, 2026, 6:16 p.m.
Last Modified :
July 9, 2026, 7:33 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-55420
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Discourse to version 2026.6.0 or later.
- Verify PDF upload processing security settings.
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-2026-55420.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55420 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-2026-55420
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-2026-55420 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55420 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.
-
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': '>= 2026.5.0-latest, < 2026.5.1'}, {'status': 'affected', 'version': '>= 2026.4.0-latest, < 2026.4.2'}, {'status': 'affected', 'version': '>= 2026.1.0-latest, < 2026.1.5'}]}] Added Description Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, under certain non-default configurations, processing of PDF uploads could be exploited to obtain RCE on the server. This issue is patched in 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5. Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-78 Added Reference https://github.com/discourse/discourse/commit/ca5a7e06167561928556afa2f237d67e459c6914 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-7wq5-jgww-5rw3