CVE-2026-55420

HIGHNVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.1 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 73% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 4 sources updated this week
8.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
8.1
EG Score
8.1(medium)
EPSS
27.0%
KEV
Not listed

Published

July 9, 2026

Last Modified

July 14, 2026

Advisory Details (2)

Auto-updated Jul 9, 2026
Patch available. Sources: github_commit, github.
github Patch Available

Remote code execution via pdf uploads · Advisory · discourse/discourse · GitHub

https://github.com/discourse/discourse/security/advisories/GHSA-7wq5-jgww-5rw3
github_commit

commit ca5a7e061675 (discourse/discourse)

Fix landed in discourse/discourse commit ca5a7e061675 — awaiting tagged release

https://github.com/discourse/discourse/commit/ca5a7e06167561928556afa2f237d67e459c6914

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 28× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 22:54 UTCEG score recompute
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 16:57 UTCEPSS rescore
  4. 2026-07-15 11:27 UTCEG score recompute
  5. 2026-07-15 02:00 UTCEPSS rescore
  6. 2026-07-15 02:00 UTCEPSS rescore
  7. 2026-07-14 23:57 UTCEG score recompute
  8. 2026-07-14 12:30 UTCEG score recompute
  9. 2026-07-14 03:13 UTCNVD updateCVSS v3 → 8.1
  10. 2026-07-14 01:25 UTCMITRE cvelistV5CVSS v3 → 7.5
  11. 2026-07-14 01:03 UTCEG score recompute▲ 0.60
  12. 2026-07-13 22:31 UTCEPSS rescore
  13. 2026-07-13 16:08 UTCNVD updateCVSS v3 → 8.1
  14. 2026-07-13 13:34 UTCEG score recompute
  15. 2026-07-13 06:13 UTCEPSS rescore
  16. 2026-07-13 06:13 UTCEPSS rescore
  17. 2026-07-13 02:06 UTCEG score recompute
  18. 2026-07-12 14:39 UTCEG score recompute
  19. 2026-07-12 05:46 UTCEPSS rescore
  20. 2026-07-12 03:12 UTCEG score recompute
  21. 2026-07-11 15:45 UTCEG score recompute
  22. 2026-07-11 08:27 UTCEPSS rescore
  23. 2026-07-11 08:27 UTCEPSS rescore
  24. 2026-07-11 04:18 UTCEG score recompute
  25. 2026-07-10 16:51 UTCEG score recompute
Show 3 more
  1. 2026-07-10 05:24 UTCEG score recompute
  2. 2026-07-09 17:56 UTCEG score recompute
  3. 2026-07-09 17:56 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-55420?
CVE-2026-55420 is a high vulnerability published on July 9, 2026. 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.
When was CVE-2026-55420 disclosed?
CVE-2026-55420 was first published in the National Vulnerability Database on July 9, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55420 actively exploited?
CVE-2026-55420 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 27.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55420?
CVE-2026-55420 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-55420?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55420, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-55420

Explore →

Is Your Infrastructure Affected by CVE-2026-55420?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs