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Vulnerability record · CVE-2026-55420 · published 9 July 2026

CVE-2026-55420: Discourse os command injection vulnerability

Discourse · Discourse

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.

8.1 CVSS 3.1 High EPSS 0.60% · top 53.3% CWE-78 · OS command injection
8.1CVSS 3.1 base score
0.60%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References
14 Jul 2026Last modified by NVD

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-55420), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.