Secure Firewall Threat DefenseApplication · Cisco
CVE-2026-20025
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 · uneditedA vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an authenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. To exploit this vulnerability, the attacker must have the OSPF secret key. This vulnerability is due to insufficient input validation when processing OSPF link-state update (LSU) packets. An attacker could exploit this vulnerability by sending crafted OSPF LSU packets. A successful exploit could allow the attacker to corrupt the heap, causing the device to reload, resulting in a DoS condition.
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 confidenceThis vulnerability exists in Cisco Secure Firewall ASA and FTD software's OSPF protocol implementation. An authenticated, adjacent attacker with the OSPF secret key can send specially crafted OSPF Link-State Update (LSU) packets containing malformed data. Due to insufficient input validation, the device experiences heap corruption when processing these packets, triggering an unexpected reload and resulting in denial of service.
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
>= 6.4.0, < 7.0.9>= 7.1.0, < 7.2.11>= 7.3.0, < 7.4.3>= 7.6.0, < 7.6.4>= 7.7.0, < 7.7.11
Adaptive Security Appliance SoftwareOperating system
>= 9.12.1, < 9.16.4.85>= 9.17.1, < 9.18.4.66>= 9.19.1, < 9.20.4>= 9.22.1.1, < 9.22.2.4>= 9.23.1, < 9.23.1.7CVSS 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
- Adjacent
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
-
Identify product type and versionLogin to the device CLI and run `show version` to identify whether the device runs ASA or FTD software and note the exact version number displayed.Affected if The device runs Cisco ASA Software or FTD Software with a version falling within the affected ranges: FTD < 7.0.9, 7.1.0-7.2.10, 7.3.0-7.4.2, 7.6.0-7.6.3, or 7.7.0-7.7.10; ASA < 9.16.4.85, 9.17.1-9.18.4.65, 9.19.1-9.20.3, 9.22.1.1-9.22.2.3, or 9.23.1-9.23.1.6
-
Verify OSPF is configuredRun `show running-config ospf` or `show ospf` in privileged exec mode to check if any OSPF process or area configuration exists.Affected if OSPF is actively configured on the device. If no OSPF configuration exists, the device is not vulnerable to this specific flaw.
-
Confirm OSPF is enabled on interfacesRun `show ospf interface brief` to list all interfaces where OSPF is enabled and processing packets.Affected if OSPF is enabled on one or more interfaces, meaning the device is actively processing OSPF packets and could receive the malformed LSU packets described in the CVE.
A device is affected if it runs a vulnerable ASA or FTD version AND has OSPF configured and enabled on at least one interface, exposing it to adjacent attackers with the OSPF secret key.
Generated from the published advisory. Verify against your own configuration.
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 · scoped7.0.97.2.117.4.3
Apply the vendor-provided security update/patch from Cisco. As an interim control, restrict OSPF adjacency to trusted segments using interface-level OSPF authentication and ACLs to limit exposure to adjacent attackers who possess the OSPF secret key.
Upgrade to first fixed version in your release train: FTD 7.0.9/7.2.11/7.4.3/7.6.4 or later; ASA 9.16.4.85/9.18.4.66/9.20.4/9.22.2.4 or later
- 1. Identify the currently running Cisco ASA or FTD version using 'show version' command
- 2. Based on your current major version, plan upgrade to the first fixed release: For FTD 6.x - upgrade to 7.0.9 or later; For FTD 7.1.x - upgrade to 7.2.11 or later; For FTD 7.3.x - upgrade to 7.4.3 or later; For FTD 7.6.x - upgrade to 7.6.4 or later
- 3. For ASA 9.12-9.15 - upgrade to 9.16.4.85 or later; For ASA 9.17 - upgrade to 9.18.4.66 or later; For ASA 9.19-9.20 - upgrade to 9.20.4 or later; For ASA 9.22.x - upgrade to 9.22.2.4 or later
- 4. Download the appropriate Cisco software image from the Cisco download portal (requires valid service contract)
- 5. Upload the new image to the device using 'copy' command or through the management interface
- 6. Perform the upgrade using 'install pip' command for FTD or 'upgrade' for ASA, or use the GUI/Firepower Management Center
- 7. Verify the upgrade completed successfully with 'show version' confirming the new fixed version
- 8. Confirm OSPF functionality is operating normally after reload
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
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20025 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-20025 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data