CVE-2026-20323

HIGHPre-NVD 8.38.3—
EchelonGraph scoreHIGH confidence

Score 8.3 from GitHub Security Advisory (severity: HIGH) published 2026-09-16. a secondary CVSS source baseline 8.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
8.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.3Exploit: 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 FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer device and obtain access at the level of the manager role, which is equivalent to root. This vulnerability is due to improper management of the TLS certificate for the sftunnel management connection. An attacker could exploit this vulnerability by connecting to the sftunnel port using a crafted TLS certificate. A successful exploit could allow the attacker to become a registered sftunnel peer with root access. Note: The attack is successful only if the sftunnel connection is down or the attack can disrupt the sftunnel connection long enough to execute the attack.

CVSS v3
8.3
EG Score
8.3(high)
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
Severity83% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
0%
KEV
Not listed

Published

September 16, 2026

Last Modified

September 18, 2026

Advisory Details (1)

Auto-updated Sep 16, 2026
No patch confirmed yet.
generic

Cisco Secure Firewall Management Center and Secure Firewall Threat Defense Software sftunnel Vulnerabilities

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmcftd-sftun-multivulns-WGVHOrN3

Vendor Advisories for CVE-2026-20323(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 16× in last 7d / 16× 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 01:57 UTCGHSA enrichment
  2. 2026-09-18 13:41 UTCGHSA enrichment
  3. 2026-09-18 12:52 UTCGHSA enrichment
  4. 2026-09-18 00:35 UTCEG score recompute
  5. 2026-09-18 00:35 UTCGHSA enrichment
  6. 2026-09-17 12:19 UTCEG score recompute
  7. 2026-09-17 12:19 UTCGHSA enrichment
  8. 2026-09-17 11:49 UTCEG score recompute
  9. 2026-09-17 11:49 UTCGHSA enrichment
  10. 2026-09-17 04:19 UTCEG score recompute
  11. 2026-09-17 04:19 UTCGHSA enrichment
  12. 2026-09-17 04:05 UTCEG score recompute
  13. 2026-09-17 04:05 UTCGHSA enrichment
  14. 2026-09-16 21:27 UTCEG score recompute
  15. 2026-09-16 20:34 UTCEG score recompute
  16. 2026-09-16 20:29 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-20323?
CVE-2026-20323 is a high vulnerability published on September 16, 2026. A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer device and obtain access at the level of the manager role, which is equivalent to root. This…
When was CVE-2026-20323 disclosed?
CVE-2026-20323 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-2026-20323 actively exploited?
CVE-2026-20323 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 99.5% of all scored CVEs.
What is the CVSS score of CVE-2026-20323?
CVE-2026-20323 has a CVSS v3 base score of 8.3 (NVD).
How do I remediate CVE-2026-20323?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20323, 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-2026-20323

Explore →

Is Your Infrastructure Affected by CVE-2026-20323?

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

Start Free Scan →Browse All CVEs