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Mallory
Medium

DoS via OSPF LSU out-of-bounds write in Cisco Secure Firewall ASA/FTD (OSPF canonicalization debug)

IdentifiersCVE-2026-20022CWE-787

A vulnerability in OSPF processing in Cisco Secure Firewall ASA Software and Cisco Secure FTD Software can be triggered when OSPF canonicalization debugging is enabled (via debug ip ospf canon). Due to insufficient input validation while processing OSPF Link State Update (LSU) packets, an unauthenticated adjacent attacker can send crafted OSPF packets that cause the device to write to memory outside the bounds of the packet data (out-of-bounds write), leading to an unexpected device reload and denial of service.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation causes the affected ASA/FTD device to reload unexpectedly, resulting in a denial-of-service condition (loss of availability) for the firewall and the traffic it handles.

Mitigation

If you can’t patch tonight, do this now.

Disable OSPF canonicalization debugging (no debug ip ospf canon) unless actively required for troubleshooting, and restrict/segment OSPF adjacency to trusted L2/L3 neighbors to reduce exposure to crafted adjacent OSPF traffic. (No additional vendor-specific mitigations were provided in the content.)

Remediation

Patch, then assume compromise.

Information currently not available in the provided content (no fixed releases or vendor remediation details were included).
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Cisco SystemsAdaptive Security Appliance Softwareoperating_system
Cisco SystemsFirepower Threat Defense Softwareapplication
Cisco SystemsSecure Firewall Asa Softwareapplication
Cisco SystemsSecure Ftd Softwareapplication

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What this page doesn’t show

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

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