Vulnerability Report

CVE-2026-55420

RCE

Title: Discourse RCE via PDF Upload Processing

RCE

Proof Of Concept

No public PoC currently indexed for CVE-2026-55420.

CWE Category CWE-78

Published Date Jul 09, 2026

Modified Date Jul 14, 2026

Exploit Status Not Found

Score 7.5 CVSS v3.1

Exploit Probability (EPSS)

0.35%

Vulnerability Summary

CVE-2026-55420: 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.

Impacted Vendors

discourse 1

Reference Links

https://github.com/discourse/discourse/commit/ca5a7e06167561928556afa2f237d67e459c6914 https://github.com/discourse/discourse/releases/tag/v2026.1.5 https://github.com/discourse/discourse/releases/tag/v2026.4.2 https://github.com/discourse/discourse/releases/tag/v2026.5.1 https://github.com/discourse/discourse/releases/tag/v2026.6.0 https://github.com/discourse/discourse/security/advisories/GHSA-7wq5-jgww-5rw3

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.5

Attack Vector

NETWORK

Complexity

HIGH

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1

Source Entity [email protected]

Severity HIGH

8.1

Attack Vector

NETWORK

Complexity

HIGH

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-55420 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

July 14, 2026 MODIFIED

Vulnerability data updated via NVD.

July 13, 2026 MODIFIED

Vulnerability data updated via NVD.

July 09, 2026 MODIFIED

Vulnerability data updated via NVD.

July 09, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity HIGH

Privileges N/A

Interaction NONE

CVSS Vector String


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

Affected Stack

No specific products linked.