Vulnerability Details 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 25.0%
CVSS Severity
CVSS v3 Score 7.5
References
- 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
Products affected by CVE-2026-55420
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cpe:2.3:a:discourse:discourse:2026.1.0
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cpe:2.3:a:discourse:discourse:2026.1.1
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cpe:2.3:a:discourse:discourse:2026.1.2
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cpe:2.3:a:discourse:discourse:2026.1.3
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cpe:2.3:a:discourse:discourse:2026.1.4
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cpe:2.3:a:discourse:discourse:2026.4.0
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cpe:2.3:a:discourse:discourse:2026.4.1
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cpe:2.3:a:discourse:discourse:2026.5.0
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cpe:2.3:a:discourse:discourse:2026.6.0