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CVE-2026-55420
Published:July 09, 2026
Updated:August 04, 2026
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.
Affected Packages
https://github.com/discourse/discourse.git (GITHUB):
Affected version(s) >=v2026.4.0 <v2026.4.2
Fix Suggestion:
Update to version v2026.4.2
https://github.com/discourse/discourse.git (GITHUB):
Affected version(s) =v2026.5.0 <v2026.5.1
Fix Suggestion:
Update to version v2026.5.1
https://github.com/discourse/discourse.git (GITHUB):
Affected version(s) >=v2026.1.0 <v2026.1.5
Fix Suggestion:
Update to version v2026.1.5
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CVSS v4
Base Score:
7.7
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
EPSS
Base Score:
0.35