CVE-2026-55420 PUBLISHED

Discourse: Remote code execution via pdf uploads

Assigner: GitHub_M
Reserved: 16.06.2026 Published: 09.07.2026 Updated: 09.07.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	discourse
Product	discourse
Versions	Version >= 2026.5.0-latest, < 2026.5.1 is affected Version >= 2026.4.0-latest, < 2026.4.2 is affected Version >= 2026.1.0-latest, < 2026.1.5 is affected

References

Problem Types

CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') CWE