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Vulnerabilities

Vulnerability · CVE-2026-20100

A vulnerability in the LUA interperter of the Remote Access SSL VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Thr…

Published Mar 4, 2026 · catalog updated Aug 11, 2026 · adaptive security appliance software

Last checked Oct 30, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-20100. EPSS is 0.33%. Act only if a listed version of adaptive security appliance software is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.33%
Remediation
Advisory link
Affected products
cpe cisco/adaptive security appliance software · cpe cisco/secure firewall threat defense

A vulnerability in the LUA interperter of the Remote Access SSL VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with a valid VPN connection to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This does not affect the management or MUS interfaces. This vulnerability is due to trusting user input without validation in the LUA interprerter. An attacker could exploit this vulnerability by sending crafted HTTP packets to the Remote Access SSL VPN server. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe cisco/adaptive security appliance software9.12.1
  • cpe cisco/adaptive security appliance software9.12.1.2
  • cpe cisco/adaptive security appliance software9.12.1.3
  • cpe cisco/adaptive security appliance software9.12.2
  • cpe cisco/adaptive security appliance software9.12.2.1
  • cpe cisco/adaptive security appliance software9.12.2.4
  • cpe cisco/adaptive security appliance software9.12.2.5
  • cpe cisco/adaptive security appliance software9.12.2.9
  • cpe cisco/secure firewall threat defense6.4.0

How to fix CVE-2026-20100

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-20100. EPSS is 0.33%. Act only if a listed version of adaptive security appliance software is installed.

Which versions are affected?

Compare what you have installed with cisco/adaptive security appliance software 9.12.1; cisco/adaptive security appliance software 9.12.1.2; cisco/adaptive security appliance software 9.12.1.3; cisco/adaptive security appliance software 9.12.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-120: Classic Buffer Overflow. EPSS 0.33%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Cisco security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 4, 2026 · NIST NVD

    Detected

    A vulnerability in the LUA interperter of the Remote Access SSL VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with a valid VPN connection to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This does not affect the management or

  2. Aug 11, 2026 · NIST NVD

    Updated

    A vulnerability in the LUA interperter of the Remote Access SSL VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with a valid VPN connection to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This does not affect the management or

Sources

  • CVE.orgVulnerability recordCVE-2026-20100

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-20100

    30-day exploitation probability 0.33%

    first.org
  • NIST NVDVulnerability recordCVE-2026-20100

    A vulnerability in the LUA interperter of the Remote Access SSL VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker with a valid VPN connection to cause the

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 30, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 30, 2026
  • CVE.orgOct 16, 2026
  • NIST NVDOct 15, 2026