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major vulnerability· requires attention

Cisco Secure Firewall (ASA/FTD) is widely deployed; unauthenticated remote DoS causing device reload can produce widespread network outages.

Networks

CVE-2026-20250

8.6
High
EPSS n/aSep 18, 2026

Unauthenticated DTLS packets can force Cisco ASA/FTD reloads (DoS).

common questions

Is CVE-2026-20250 being exploited?

Not confirmed. CVE-2026-20250 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.

How severe is CVE-2026-20250?

CVE-2026-20250 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-2026-20250?

Not known from our data. No patch reference has been recorded for CVE-2026-20250, 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-2026-20250 affect?

CVE-2026-20250 affects Cisco Secure Firewall ASA Software, Cisco Secure Firewall Threat Defense (FTD) Software, Cisco Secure Firewall 3100 Series, Cisco Secure Firewall 4200 Series. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-20250?

Apply Cisco mitigations, block/uninspect DTLS from untrusted sources, restrict access, install vendor updates when published.

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

executive summary
technical analysis
affected
Cisco Secure Firewall ASA SoftwareCisco Secure Firewall Threat Defense (FTD) SoftwareCisco Secure Firewall 3100 SeriesCisco Secure Firewall 4200 Series
impact

Remote unauthenticated attacker can send crafted DTLS traffic to trigger device reloads, causing firewall outage and network disruption.

action required

Immediate action required

affected versions
Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
  • affected9.23.1
  • affected9.22.1.1
  • affected9.22.1.3
  • affected9.22.1.6
  • affected9.22.2
  • affected9.23.1.3
  • affected9.22.2.4
  • affected9.23.1.7
  • affected9.22.2.9
  • affected9.23.1.13
  • affected9.22.2.13
  • affected9.23.1.19
  • affected9.22.2.14
  • affected9.24.1
  • affected9.23.1.22
  • affected9.22.2.20
  • affected9.23.1.26
Cisco Cisco Secure Firewall Threat Defense (FTD) Software
  • affected7.6.0
  • affected7.7.0
  • affected7.6.1
  • affected7.6.2
  • affected7.7.10
  • affected7.7.11
  • affected7.6.2.1
  • affected7.7.10.1
  • affected7.6.4
  • affected10.0.0

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.

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
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