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🛡️ CVE-2026-20100 — adaptive-security-appliance-software

🟠 CVSS 7.7 — High ✅ No Known Exploit CWE-120 NVD
7.7
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-20100 is classified as CWE-120: Classic Buffer Overflow. Input is copied into a fixed-size buffer without a length check, overwriting memory past the end of it.

Affected software

CVE-2026-20100 is recorded against 2 packages.

  • adaptive-security-appliance-software
  • secure-firewall-threat-defense

Timeline and source

Published on 4 March 2026 and last revised on 11 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

sec.cloudapps.cisco.com

Other advisories for this package

adaptive-security-appliance-software has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-120: Classic Buffer Overflow) in other software:

Details

Severity HIGH
CVSS Score 7.7
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
CWE CWE-120
Public Exploit ✅ No
Source NVD
Published 2026-03-04
Updated 2026-08-20
Modified 2026-08-11
Fix URL N/A

Affected Packages

Software From version Fixed in
adaptive-security-appliance-software — —
secure-firewall-threat-defense — —

Similar Threats

Site Security Check

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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