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major vulnerability· requires attention

Impacts widely deployed Cisco Secure FMC/FTD appliances; DoS can disrupt enterprise network security and management.

Networks

CVE-2026-20295

8.6
High
EPSS 0.57%

Remote DoS via sftunnel TLS memory exhaustion in Cisco Secure FMC/FTD

exploited
No known exploitation not in CISA KEV as of our last sync
fix
No fixed release stated by the publisher
likelihood
EPSS 0.57%top 53% of scored CVEs
Published 16 Sept 2026Analysed here 18 Sept 2026CVSS scored by the publisher (CNA)
common questions

Is CVE-2026-20295 being exploited?

Not confirmed. CVE-2026-20295 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.57% probability of exploitation in the next 30 days.

How severe is CVE-2026-20295?

CVE-2026-20295 is rated High with a CVSS score of 8.6. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-20295?

Not known from our data. No patch reference has been recorded for CVE-2026-20295, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.

What does CVE-2026-20295 affect?

CVE-2026-20295 affects Cisco Secure FMC Software, Cisco Secure FTD Software. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-20295?

Apply vendor updates ASAP or block/limit sftunnel traffic from untrusted networks.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Cisco Secure FMC SoftwareCisco Secure FTD Software
impact

Unauthenticated remote memory exhaustion via crafted sftunnel TLS frames causing device DoS and loss of management/traffic inspection.

action required

Immediate action required

affected versions
Cisco Cisco Secure Firewall Management Center (FMC)
  • affected7.0.0
  • affected7.0.0.1
  • affected7.0.1
  • affected7.0.1.1
  • affected7.0.2
  • affected7.2.0
  • affected7.0.2.1
  • affected7.0.3
  • affected7.2.0.1
  • affected7.0.4
  • affected7.2.1
  • affected7.0.5
  • affected7.3.0
  • affected7.2.2
  • affected7.3.1
  • affected7.2.3
  • affected7.2.3.1
  • affected7.2.4
  • affected7.0.6
  • affected7.2.4.1
  • affected7.2.5
  • affected7.3.1.1
  • affected7.4.0
  • affected7.0.6.1
  • affected7.2.5.1
  • affected7.4.1
  • affected7.2.6
  • affected7.4.1.1
  • affected7.0.6.2
  • affected7.2.7
  • affected7.2.5.2
  • affected7.3.1.2
  • affected7.2.8
  • affected7.6.0
  • affected7.4.2
  • affected7.2.8.1
  • affected7.0.6.3
  • affected7.4.2.1
  • affected7.2.9
  • affected7.0.7
  • affected7.7.0
  • affected7.4.2.2
  • affected7.2.10
  • affected7.6.1
  • affected7.4.2.3
  • affected7.0.8
  • affected7.6.2
  • affected7.7.10
  • affected7.2.10.1
  • affected7.0.8.1
  • affected7.6.2.1
  • affected7.2.10.2
  • affected7.7.10.1
  • affected7.4.2.4
  • affected7.4.3
  • affected7.6.3
  • affected7.7.11
  • affected7.6.4
  • affected10.0.0
  • affected7.4.4
  • affected7.4.5
  • affected7.0.9
  • affected7.2.11
  • affected7.7.12
  • affected7.6.5
  • affected7.4.6
  • affected10.0.1
Cisco Cisco Secure Firewall Threat Defense (FTD) Software
  • affected7.0.0
  • affected7.0.0.1
  • affected7.0.1
  • affected7.0.1.1
  • affected7.0.2
  • affected7.2.0
  • affected7.0.2.1
  • affected7.0.3
  • affected7.2.0.1
  • affected7.0.4
  • affected7.2.1
  • affected7.0.5
  • affected7.3.0
  • affected7.2.2
  • affected7.2.3
  • affected7.3.1
  • affected7.2.4
  • affected7.0.6
  • affected7.2.5
  • affected7.2.4.1
  • affected7.3.1.1
  • affected7.4.0
  • affected7.0.6.1
  • affected7.2.5.1
  • affected7.4.1
  • affected7.2.6
  • affected7.0.6.2
  • affected7.4.1.1
  • affected7.2.7
  • affected7.2.5.2
  • affected7.3.1.2
  • affected7.2.8
  • affected7.6.0
  • affected7.4.2
  • affected7.2.8.1
  • affected7.0.6.3
  • affected7.4.2.1
  • affected7.2.9
  • affected7.0.7
  • affected7.7.0
  • affected7.4.2.2
  • affected7.2.10
  • affected7.6.1
  • affected7.4.2.3
  • affected7.0.8
  • affected7.6.2
  • affected7.7.10
  • affected7.7.11
  • affected7.0.8.1
  • affected7.6.2.1
  • affected7.7.10.1
  • affected7.4.2.4
  • affected7.2.10.2
  • affected7.4.3
  • affected7.6.4
  • affected10.0.0
  • affected7.4.4
  • affected7.0.9
  • affected7.2.11

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

cisa ssvc

exploitation
none
automatable
yes
technical impact
partial

Assessed by CISA 17 Sept 2026 (SSVC 2.0.3).

timeline

  1. 16 Sept 2026Published
  2. 17 Sept 2026CISA SSVC assessment: exploitation none · 1 day later
  3. 17 Sept 2026CVE record last updated · same day later
  4. 18 Sept 2026Analysed by vulneraibility.com · 1 day later
how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
NVDCVE.orgCVE DetailsSource
1 reference in the CVE record: 1 link

sources

  • CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
  • NVD: CVSS and CPE data
  • CISA Vulnrichment (ADP): SSVC decision points
  • FIRST EPSS: exploit probability and percentile
  • Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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