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VulnerabilityPublished

CVE-2026-20022: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software · Use of Out-of-range Pointer Offset

Affects Cisco Secure Firewall Adaptive Security Appliance (ASA) SoftwareSource CVE Database V5

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Not known to be exploited · CVSS 6.1 Medium.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
6.1Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
CiscoCisco Secure Firewall Adaptive Security Appliance (ASA) SoftwareAffected
  • 9.12.1 – 9.23.1.22
163 affected builds
Fixed in–
CiscoCisco Secure Firewall Threat Defense (FTD) SoftwareAffected
  • 6.4.0 – 7.7.10.1
76 affected builds
Fixed in–

AI-suggested

To mitigate CVE-2026-20022, organizations should first verify whether the OSPF canonicalization debug feature ('debug ip ospf canon') is enabled on affected Cisco ASA or FTD devices. If enabled, it should be disabled immediately to eliminate the vulnerable code path. Cisco has not provided explicit patch links in the provided data, so organizations should monitor Cisco security advisories for official patches or updates addressing this vulnerability and apply them promptly once available. Network segmentation and strict control of adjacency to critical firewall devices can reduce exposure by limiting which hosts can send OSPF packets. Implementing robust network monitoring to detect unusual OSPF traffic patterns may help identify exploitation attempts. Additionally, organizations should review and harden OSPF configurations, ensuring authentication mechanisms are in place where possible, even though this vulnerability does not require authentication. Regular firmware and software updates, combined with configuration audits, will help maintain a secure posture against similar protocol-level vulnerabilities.

Description

A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition when OSPF canonicalization debug is enabled by using the command debug ip ospf canon. This vulnerability is due to insufficient input validation when processing OSPF LSU packets. An attacker could exploit this vulnerability by sending crafted unauthenticated OSPF packets. A successful exploit could allow the attacker to write to memory outside of the packet data, causing the device to reload, resulting in a DoS condition.

References

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