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
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.1Exploit: None knownExposed: 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)
EG Risk
37(Track)
EG Risk 37/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity81% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
27%
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 11× in last 7d / 34× 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. 2026-07-30 01:30 UTCEPSS rescore
  2. 2026-07-29 00:06 UTCEG score recompute
  3. 2026-07-28 15:37 UTCEPSS rescore
  4. 2026-07-28 00:33 UTCEG score recompute
  5. 2026-07-26 23:46 UTCEG score recompute
  6. 2026-07-26 14:54 UTCEPSS rescore
  7. 2026-07-26 12:18 UTCEG score recompute
  8. 2026-07-25 14:18 UTCEPSS rescore
  9. 2026-07-24 14:18 UTCEPSS rescore
  10. 2026-07-23 14:18 UTCEPSS rescore
  11. 2026-07-23 03:20 UTCEG score recompute
  12. 2026-07-22 14:08 UTCEPSS rescore
  13. 2026-07-20 17:08 UTCEPSS rescore
  14. 2026-07-19 14:31 UTCEPSS rescore
  15. 2026-07-19 14:31 UTCEPSS rescore
  16. 2026-07-19 02:29 UTCEPSS rescore
  17. 2026-07-18 10:04 UTCEPSS rescore
  18. 2026-07-16 17:03 UTCEPSS rescore
  19. 2026-07-15 16:57 UTCEPSS rescore
  20. 2026-07-15 16:57 UTCEPSS rescore
  21. 2026-07-15 02:00 UTCEPSS rescore
  22. 2026-07-15 02:00 UTCEPSS rescore
  23. 2026-07-14 03:13 UTCNVD updateCVSS v3 → 8.1
  24. 2026-07-14 01:25 UTCMITRE cvelistV5CVSS v3 → 7.5
  25. 2026-07-14 01:03 UTCEG score recompute▲ 0.60
Show 9 more
  1. 2026-07-13 22:31 UTCEPSS rescore
  2. 2026-07-13 16:08 UTCNVD updateCVSS v3 → 8.1
  3. 2026-07-13 06:13 UTCEPSS rescore
  4. 2026-07-13 06:13 UTCEPSS rescore
  5. 2026-07-12 05:46 UTCEPSS rescore
  6. 2026-07-11 08:27 UTCEPSS rescore
  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-09 17:56 UTCEG score recompute
  9. 2026-07-09 17:56 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

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 0% probability of exploitation in the next 30 days, which ranks it in the top 72.6% of all scored CVEs.
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