CVE Intelligence
High Memory corruption

CVE-2026-20012 — Missing Release of Memory after Effective Lifetime in Cisco Adaptive Security Appliance Software

A vulnerability in the Internet Key Exchange version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition on an affected device. This vulnerability is due to improper parsing of IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. A successful exploit of Cisco IOS Software and IOS XE Software could allow the attacker to cause the affected device to reload, resulting in a DoS condition. A successful exploit of Cisco Secure Firewall ASA Software and Secure FTD Software could allow the attacker to partially exhaust system memory, resulting in system instability, such as the inability to establish new IKEv2 VPN sessions. A manual reboot of the device is required to recover from this condition.

Published Mar 25, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: cisco

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.4% (30-day exploitation probability)+4
  • Technical severity (high)+6
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.35%
ahead of 27% of scored CVEs · Oct 14, 2026
Affects
Cisco
Adaptive Security Appliance Software and 1 more
CVSS base
8.6
High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Cisco Adaptive Security Appliance Software, Cisco Cisco IOS XE Software).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Cisco Adaptive Security Appliance Software version 9.18.4.52version 9.18.4.53version 9.18.4.57version 9.18.4.66version 9.18.4.67version 9.18.4.68version 9.19.1version 9.19.1.5
and 227 more version 9.19.1.9version 9.19.1.12version 9.19.1.18version 9.19.1.22version 9.19.1.24version 9.19.1.27version 9.19.1.28version 9.19.1.31version 9.19.1.37version 9.19.1.38version 9.19.1.42version 9.20.1version 9.20.1.5version 9.20.2version 9.20.2.10version 9.20.2.21version 9.20.2.22version 9.20.3version 9.20.3.4version 9.20.3.7version 9.20.3.9version 9.20.3.10version 9.20.3.13version 9.20.3.16version 9.20.3.20version 9.20.4version 9.20.4.7version 9.22.1.1version 9.22.1.2version 9.22.1.3version 9.22.1.6version 9.22.2version 9.22.2.4version 9.22.2.9version 9.23.1version 9.23.1.3version 9.23.1.7version 9.23.1.13version 9.12.4.29version 9.12.4.30version 9.12.4.35version 9.12.4.37version 9.12.4.38version 9.12.4.39version 9.12.4.40version 9.12.4.41version 9.12.4.47version 9.12.4.48version 9.12.4.50version 9.12.4.52version 9.12.4.54version 9.12.4.55version 9.12.4.56version 9.12.4.58version 9.12.4.62version 9.12.4.65version 9.12.4.67version 9.14.1version 9.14.1.6version 9.14.1.10version 9.14.1.15version 9.14.1.19version 9.14.1.30version 9.14.2version 9.14.2.4version 9.14.2.8version 9.14.2.13version 9.14.2.15version 9.14.3version 9.14.3.1version 9.14.3.9version 9.14.3.11version 9.14.3.13version 9.14.3.15version 9.14.3.18version 9.14.4version 9.14.4.6version 9.14.4.7version 9.14.4.12version 9.14.4.13version 9.14.4.14version 9.14.4.15version 9.14.4.17version 9.14.4.22version 9.14.4.23version 9.14.4.24version 9.16.1version 9.16.1.28version 9.16.2version 9.16.2.3version 9.16.2.7version 9.16.2.11version 9.16.2.13version 9.16.2.14version 9.16.3version 9.16.3.3version 9.16.3.14version 9.16.3.15version 9.16.3.19version 9.16.3.23version 9.16.4version 9.16.4.9version 9.16.4.14version 9.16.4.19version 9.16.4.27version 9.16.4.38version 9.16.4.39version 9.16.4.42version 9.16.4.48version 9.16.4.55version 9.16.4.57version 9.16.4.61version 9.16.4.62version 9.16.4.67version 9.16.4.70version 9.16.4.71version 9.16.4.76version 9.16.4.82version 9.16.4.84version 9.17.1version 9.17.1.7version 9.17.1.9version 9.17.1.10version 9.17.1.11version 9.17.1.13version 9.17.1.15version 9.17.1.20version 9.17.1.30version 9.17.1.33version 9.17.1.39version 9.17.1.45version 9.17.1.46version 9.18.1version 9.18.1.3version 9.18.2version 9.18.2.5version 9.18.2.7version 9.18.2.8version 9.18.3version 9.18.3.39version 9.18.3.46version 9.18.3.53version 9.18.3.55version 9.18.3.56version 9.18.4version 9.18.4.5version 9.18.4.8version 9.18.4.22version 9.18.4.24version 9.18.4.29version 9.18.4.34version 9.18.4.40version 9.18.4.47version 9.18.4.50version 9.8.1version 9.8.1.5version 9.8.1.7version 9.8.2version 9.8.2.8version 9.8.2.14version 9.8.2.15version 9.8.2.17version 9.8.2.20version 9.8.2.24version 9.8.2.26version 9.8.2.28version 9.8.2.33version 9.8.2.35version 9.8.2.38version 9.8.2.45version 9.8.3version 9.8.3.8version 9.8.3.11version 9.8.3.14version 9.8.3.16version 9.8.3.18version 9.8.3.21version 9.8.3.26version 9.8.3.29version 9.8.4version 9.8.4.3version 9.8.4.7version 9.8.4.8version 9.8.4.10version 9.8.4.12version 9.8.4.15version 9.8.4.17version 9.8.4.20version 9.8.4.22version 9.8.4.25version 9.8.4.26version 9.8.4.29version 9.8.4.32version 9.8.4.33version 9.8.4.34version 9.8.4.35version 9.8.4.39version 9.8.4.40version 9.8.4.41version 9.8.4.43version 9.8.4.44version 9.8.4.45version 9.8.4.46version 9.8.4.48version 9.12.1version 9.12.1.2version 9.12.1.3version 9.12.2version 9.12.2.1version 9.12.2.4version 9.12.2.5version 9.12.2.9version 9.12.3version 9.12.3.2version 9.12.3.7version 9.12.3.9version 9.12.3.12version 9.12.4version 9.12.4.2version 9.12.4.4version 9.12.4.7version 9.12.4.8version 9.12.4.10version 9.12.4.13version 9.12.4.18version 9.12.4.24version 9.12.4.26
Vulnerable NIST National Vulnerability Database
Cisco Cisco IOS XE Software version 17.15.2aversion 17.13.1version 17.13.1aversion 17.14.1version 17.14.1aversion 17.15.1version 17.15.1wversion 17.15.1a
and 57 more version 17.15.2version 17.15.1bversion 17.15.1xversion 17.15.1zversion 17.15.3version 17.15.2cversion 17.12.6bversion 17.15.1yversion 17.15.2bversion 17.15.3aversion 17.15.4version 17.15.3bversion 17.15.4dversion 17.15.4eversion 17.16.1version 17.16.1aversion 17.17.1version 17.18.1version 17.18.1wversion 17.18.1aversion 17.12.3aversion 17.9.7bversion 17.11.1version 17.11.1aversion 17.12.1version 17.12.1wversion 17.12.1aversion 17.12.1xversion 17.12.2version 17.12.3version 17.12.2aversion 17.12.1yversion 17.12.1zversion 17.12.4version 17.9.7aversion 17.12.1z1version 17.12.1z2version 17.12.4aversion 17.12.5version 17.12.4bversion 17.12.1z3version 17.12.5aversion 17.12.1z4version 17.12.6version 17.12.5bversion 17.12.5cversion 17.12.6aversion 17.12.5dversion 16.12.3aversion 16.12.4aversion 16.12.5version 16.12.6version 16.12.1z1version 16.12.5aversion 16.12.5bversion 16.12.1z2version 16.12.6a
Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.6 CVSS 3.1 High 3.9 4.0 psirt@cisco.com via NIST National Vulnerability Database
8.6 CVSS 3.1 High — — cisco via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H (score shown at the top: psirt@cisco.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-401 · Missing Release of Memory after Effective Lifetime

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.35%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · cisco/ios, cisco/cisco secure firewall adaptive security appliance (asa) software, cisco/cisco ios xe software, cisco/ci
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 8.6
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Mar 25, 2026 · cisco

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

Elsewhere on this site

Cisco
every CVE for this vendor
Memory corruption
same class
CWE-401
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-20349 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability KEV Aug 11, 2026
  • CVE-2026-20301 A vulnerability in the Extensible Messaging Client Protocol (XMCP), also referred to as… Aug 5, 2026
  • CVE-2026-20272 Injection in Cisco Ios Xe Aug 5, 2026
  • CVE-2026-20273 Improper Input Validation in Cisco Ios Xe Aug 5, 2026
  • CVE-2026-20270 As part of Cisco's ongoing commitment to proactive security and product quality, the… Aug 5, 2026
  • CVE-2026-20271 As part of Cisco's ongoing commitment to proactive security and product quality, the… Aug 5, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-20012 is "Missing Release of Memory after Effective Lifetime in Cisco Adaptive Security Appliance Software", rated High. It affects Adaptive Security Appliance Software (Cisco); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.6 describes technical severity. EPSS 0.35% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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