VulnerabilityAnalyzed
CVE-2026-55420
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.
HIGH 8.1EPSS 0.60%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.60%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- 8.1 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.60% probability · 47th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-78
- Affected
- discourse/discourse
- Source
- security-advisories@github.com
References
- https://github.com/discourse/discourse/commit/ca5a7e06167561928556afa2f237d67e459c6914Patch
- https://github.com/discourse/discourse/releases/tag/v2026.1.5Release Notes
- https://github.com/discourse/discourse/releases/tag/v2026.4.2Release Notes
- https://github.com/discourse/discourse/releases/tag/v2026.5.1Release Notes
- https://github.com/discourse/discourse/releases/tag/v2026.6.0Release Notes
- https://github.com/discourse/discourse/security/advisories/GHSA-7wq5-jgww-5rw3Mitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.