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Fencer Vulns
high 8.6

CVE-2026-20082 json

A vulnerability in the handling of the embryonic connection limits in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software coul…

published 2026-03-04 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-9471

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

A vulnerability in the handling of the embryonic connection limits in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause incoming TCP SYN packets to be dropped incorrectly. This vulnerability is due to improper handling of new, incoming TCP connections that are destined to management or data interfaces when the device is under a TCP SYN flood attack. An attacker could exploit this vulnerability by sending a crafted stream of traffic to an affected device. A successful exploit could allow the attacker to prevent all incoming TCP connections to the device from being established, including remote management access, Remote Access VPN (RAVPN) connections, and all network protocols that are TCP-based. This results in a denial of service (DoS) condition for affected features.

Patch / fix

  • cisco adaptive_security_appliance_software 9.20.4.19

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected products

  • Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software

Classification

Weakness
  • CWE-772 Missing Release of Resource after Effective Lifetime

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.