Discourse: Remote code execution via pdf uploads

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-55420
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-09 18:16:54 UTC
Updated2026-07-09 19:33:38 UTC
DescriptionDiscourse 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

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

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

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Discourse Discourse affected >= 2026.5.0-latest, < 2026.5.1 Not specified
CNA Discourse Discourse affected >= 2026.4.0-latest, < 2026.4.2 Not specified
CNA Discourse Discourse affected >= 2026.1.0-latest, < 2026.1.5 Not specified

References

ReferenceSourceLinkTags
github.com/discourse/discourse/releases/tag/v2026.5.1 [email protected] github.com
github.com/discourse/discourse/commit/ca5a7e06167561928556afa2f237d67e45... [email protected] github.com
github.com/discourse/discourse/releases/tag/v2026.6.0 [email protected] github.com
github.com/discourse/discourse/releases/tag/v2026.1.5 [email protected] github.com
github.com/discourse/discourse/security/advisories/GHSA-7wq5-jgww-5rw3 [email protected] github.com
github.com/discourse/discourse/releases/tag/v2026.4.2 [email protected] github.com
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