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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.

PUBLISHED Reserved 2026-06-16 | Published 2026-07-09 | Updated 2026-07-14 | Assigner GitHub_M




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

Problem types

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

Product status

>= 2026.5.0-latest, < 2026.5.1
affected

>= 2026.4.0-latest, < 2026.4.2
affected

>= 2026.1.0-latest, < 2026.1.5
affected

References

github.com/...course/security/advisories/GHSA-7wq5-jgww-5rw3

github.com/...ommit/ca5a7e06167561928556afa2f237d67e459c6914

github.com/discourse/discourse/releases/tag/v2026.1.5

github.com/discourse/discourse/releases/tag/v2026.4.2

github.com/discourse/discourse/releases/tag/v2026.5.1

github.com/discourse/discourse/releases/tag/v2026.6.0

cve.org (CVE-2026-55420)

nvd.nist.gov (CVE-2026-55420)

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