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Secure Firewall Threat DefenseApplication · Cisco

CVE-2026-20050

MEDIUM · 6.8 CVSS v3.1 Published 2026-03-04
Fix available
A fix is available. Upgrade to 7.2.11 / 7.4.4 or later.
See remediation →
77/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the Do Not Decrypt exclusion feature of the SSL decryption feature of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper memory management during the inspection of TLS 1.2 encrypted traffic. An attacker could exploit this vulnerability by sending crafted TLS 1.2 encrypted traffic through an affected device. A successful exploit could allow the attacker to cause a reload of an affected device. Note: This vulnerability only affects traffic that is encrypted by TLS 1.2. Other versions of TLS are not affected.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A memory management flaw in the TLS 1.2 inspection path within Cisco FTD's SSL decryption feature's Do Not Decrypt exclusion allows an unauthenticated remote attacker to trigger a device reload by sending specially crafted TLS 1.2 traffic through the affected device.

MitigationApply the Cisco-provided patch for FTD when available; until then, consider restricting inbound TLS 1.2 traffic from untrusted sources or modifying Do Not Decrypt exclusion rules to exclude problematic traffic patterns.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Secure Firewall Threat DefenseApplication
Affected:>= 7.1.0, < 7.2.11>= 7.3.0, < 7.4.4>= 7.6.0, < 7.6.4>= 7.7.0, < 7.7.11

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check FTD software version
    Run 'show version' or 'show running-config system | include version' to display the installed Cisco FTD software version
    Affected if The version falls within these ranges: >= 7.1.0 and < 7.2.11; >= 7.3.0 and < 7.4.4; >= 7.6.0 and < 7.6.4; >= 7.7.0 and < 7.7.11
  2. Verify SSL decryption policy is enabled
    Run 'show ssl-decryption' or access the SSL Decryption policy page in FTD management interface to confirm SSL decryption is active
    Affected if SSL decryption policy is enabled and configured
  3. Confirm Do Not Decrypt exclusion rules exist
    Run 'show ssl-decryption policy' or inspect the SSL decryption policy configuration to list all Do Not Decrypt exclusions
    Affected if One or more Do Not Decrypt exclusion rules are configured
  4. Verify TLS 1.2 traffic inspection is active
    Check SSL decryption policy settings to confirm TLS 1.2 inspection is enabled, or monitor traffic logs for TLS 1.2 connections being inspected
    Affected if TLS 1.2 traffic is being processed through the SSL decryption inspection path

You are affected if your FTD version is within the vulnerable ranges AND SSL decryption with Do Not Decrypt exclusions is enabled, allowing specially crafted TLS 1.2 traffic to trigger a device reload.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.2.11 / 7.4.4 / 7.6.4 or later
Fixed in 7.2.117.4.47.6.4
Interim mitigation

Apply the Cisco-provided patch for FTD when available; until then, consider restricting inbound TLS 1.2 traffic from untrusted sources or modifying Do Not Decrypt exclusion rules to exclude problematic traffic patterns.

Recommended fix High confidence

Upgrade to FTD 7.2.11 or later (for 7.1.x-7.2.x), 7.4.4 or later (for 7.3.x-7.4.x), 7.6.4 or later (for 7.6.x), or 7.7.11 or later (for 7.7.x)

  1. 1. Identify the current FTD software version using 'show version' or FMC interface
  2. 2. Determine which version range your current release falls into (7.1.x-7.2.x, 7.3.x-7.4.x, 7.6.x, or 7.7.x)
  3. 3. Download the appropriate fixed software version from Cisco (7.2.11, 7.4.4, 7.6.4, or 7.7.11 or later) from Cisco's software download center
  4. 4. Schedule a maintenance window as the upgrade will require a device reload
  5. 5. Back up the current configuration via FMC or CLI using 'export-configuration'
  6. 6. Upload the new FTD software image to FMC or directly to the device
  7. 7. Install the upgrade via FMC (Device > Device Management > Upgrade) or via CLI using 'upgrade' command
  8. 8. Confirm the upgrade completed successfully with 'show version' showing the new fixed version
Caveat Standard FTD upgrade considerations apply - ensure compatibility with FMC version and review Cisco release notes for any migration caveats

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Secure Firewall Threat Defense Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-20050 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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