Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-55420

Severity CVSS v4.0:
Pending analysis
Type:
CWE-78 OS Command Injections
Publication date:
09/07/2026
Last modified:
14/07/2026

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.

Impact

Vector 3.x
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 7.50 HIGH
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x
7.50
Severity 3.x
HIGH

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* 2026.1.0 (including) 2026.1.5 (excluding)
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* 2026.4.0 (including) 2026.4.2 (excluding)
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* 2026.5.0 (including) 2026.5.1 (excluding)
cpe:2.3:a:discourse:discourse:2026.6.0:*:*:*:latest:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools