CVE-2026-20324

CRITICALPre-NVD 9.99.9—
EchelonGraph scoreHIGH confidence

Score 9.9 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-16. a secondary CVSS source baseline 9.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
9.9EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.9Exploit: None knownExposed: 0

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

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, remote attacker to execute arbitrary commands as root. This vulnerability exists because a registered sftunnel peer has incorrect permissions to write an arbitrary file to any location on the device. An attacker could exploit this vulnerability by hijacking the sftunnel communication connection or being a valid registered sftunnel peer and sending an sftunnel command to write a malicious file to the disk of an affected device. A successful exploit could allow the attacker to write a file to the device that is executed with root privileges. To exploit this vulnerability, the attacker must have valid user credentials on the affected device.

CVSS v3
9.9
EG Score
9.9(high)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity99% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
38%
KEV
Not listed

Published

September 16, 2026

Last Modified

September 18, 2026

Advisory Details (1)

Auto-updated Sep 18, 2026
No patch confirmed yet.
generic

Cisco Secure Firewall Management Center Software sftunnel Root Arbitrary Code Execution Vulnerability

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-sftunn-codex-c3O4Jft2

Vendor Advisories for CVE-2026-20324(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 25× in last 7d / 25× 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. 2026-09-19 05:31 UTCGHSA enrichment
  2. 2026-09-19 01:22 UTCGHSA enrichment
  3. 2026-09-18 21:14 UTCEG score recompute
  4. 2026-09-18 21:14 UTCGHSA enrichment
  5. 2026-09-18 19:27 UTCEPSS rescore
  6. 2026-09-18 17:01 UTCGHSA enrichment
  7. 2026-09-18 12:52 UTCGHSA enrichment
  8. 2026-09-18 08:43 UTCGHSA enrichment
  9. 2026-09-18 04:34 UTCEG score recompute
  10. 2026-09-18 04:34 UTCGHSA enrichment
  11. 2026-09-18 04:04 UTCEG score recompute
  12. 2026-09-18 04:04 UTCGHSA enrichment
  13. 2026-09-18 02:18 UTCGHSA enrichment
  14. 2026-09-17 22:09 UTCEG score recompute
  15. 2026-09-17 22:09 UTCGHSA enrichment
  16. 2026-09-17 17:59 UTCEG score recompute
  17. 2026-09-17 17:59 UTCGHSA enrichment
  18. 2026-09-17 13:35 UTCGHSA enrichment
  19. 2026-09-17 09:26 UTCGHSA enrichment
  20. 2026-09-17 05:17 UTCGHSA enrichment
  21. 2026-09-17 01:08 UTCEG score recompute
  22. 2026-09-17 01:08 UTCGHSA enrichment
  23. 2026-09-16 20:31 UTCEG score recompute
  24. 2026-09-16 20:09 UTCEG score recompute
  25. 2026-09-16 20:09 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-20324?
CVE-2026-20324 is a critical vulnerability published on September 16, 2026. A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, remote attacker to execute arbitrary commands as root. This vulnerability exists because a registered sftunnel peer has incorrect permissions…
When was CVE-2026-20324 disclosed?
CVE-2026-20324 was first published in the National Vulnerability Database on September 16, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-20324 actively exploited?
CVE-2026-20324 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 62.3% of all scored CVEs.
What is the CVSS score of CVE-2026-20324?
CVE-2026-20324 has a CVSS v3 base score of 9.9 (NVD).
How do I remediate CVE-2026-20324?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20324, 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

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