4.3

CVE-2026-20021: cisco adaptive_security_appliance_software

CVSS: 4.3v3.1MediumAnalyzed
Published 04-03-2026Last modified 04-03-2026
Open JSON

Vulnerability summary

CVE-2026-20021 is a medium (CVSS 4.3) vulnerability in cisco adaptive_security_appliance_software. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9.6% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.20%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 04-03-2026
    PublishedVulnerability first disclosed.
  2. 04-03-2026
    Last modifiedVulnerability information updated.

Description

A vulnerability in the OSPF protocol of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, adjacent attacker to exhaust memory on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to improperly validating input by the OSPF protocol when parsing packets. An attacker could exploit this vulnerability by by sending crafted OSPF packets to an affected device. A successful exploit could allow the attacker to exhaust memory on the affected device, resulting in a DoS condition.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.20%

Chance of exploitation in the next 30 days

Percentile

10%

Versus all other CVEs

30-day change

0.00 pp

From 0.20% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.20%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cisco4 products
  • adaptive_security_appliance_software≥ 9.12.1, ≤ 9.12.4.67 | ≥ 9.16.1, ≤ 9.16.4.85 | ≥ 9.17.1, ≤ 9.17.1.46 | ≥ 9.18.1, ≤ 9.18.4.68 | ≥ 9.19.1, ≤ 9.19.1.42 | ≥ 9.20.1, ≤ 9.20.4.14 | ≥ 9.22.1.1, ≤ 9.22.2.14 | ≥ 9.23.1, ≤ 9.23.1.22
  • cisco secure firewall adaptive security appliance (asa) software9.12.1 | 9.12.1.2 | 9.12.1.3 | 9.12.2 | 9.12.2.4 | 9.12.2.5 | 9.12.2.9 | 9.12.3 | 9.12.3.2 | 9.12.3.7 | 9.12.4 | 9.12.3.12 | 9.12.3.9 | 9.12.2.1 | 9.12.4.2 | 9.12.4.4 | 9.12.4.7 | 9.12.4.10 | 9.12.4.13 | 9.12.4.8 | 9.12.4.18 | 9.12.4.24 | 9.12.4.26 | 9.12.4.29 | 9.12.4.30 | 9.12.4.35 | 9.12.4.37 | 9.12.4.38 | 9.12.4.39 | 9.12.4.40 | 9.12.4.41 | 9.12.4.47 | 9.12.4.48 | 9.12.4.50 | 9.12.4.52 | 9.12.4.54 | 9.12.4.55 | 9.12.4.56 | 9.12.4.58 | 9.12.4.62 | 9.12.4.65 | 9.12.4.67 | 9.16.1 | 9.16.1.28 | 9.16.2 | 9.16.2.3 | 9.16.2.7 | 9.16.2.11 | 9.16.2.13 | 9.16.2.14 | 9.16.3 | 9.16.3.3 | 9.16.3.14 | 9.16.3.15 | 9.16.3.19 | 9.16.3.23 | 9.16.4 | 9.16.4.9 | 9.16.4.14 | 9.16.4.19 | 9.16.4.27 | 9.16.4.38 | 9.16.4.39 | 9.16.4.42 | 9.16.4.48 | 9.16.4.55 | 9.16.4.57 | 9.16.4.61 | 9.16.4.62 | 9.16.4.67 | 9.16.4.70 | 9.16.4.71 | 9.16.4.76 | 9.16.4.82 | 9.16.4.84 | 9.16.4.85 | 9.17.1 | 9.17.1.7 | 9.17.1.9 | 9.17.1.10 | 9.17.1.11 | 9.17.1.13 | 9.17.1.15 | 9.17.1.20 | 9.17.1.30 | 9.17.1.33 | 9.17.1.39 | 9.17.1.45 | 9.17.1.46 | 9.18.1 | 9.18.1.3 | 9.18.2 | 9.18.2.5 | 9.18.2.7 | 9.18.2.8 | 9.18.3 | 9.18.3.39 | 9.18.3.46 | 9.18.3.53 | 9.18.3.55 | 9.18.3.56 | 9.18.4 | 9.18.4.5 | 9.18.4.8 | 9.18.4.22 | 9.18.4.24 | 9.18.4.29 | 9.18.4.34 | 9.18.4.40 | 9.18.4.47 | 9.18.4.50 | 9.18.4.52 | 9.18.4.53 | 9.18.4.57 | 9.18.4.66 | 9.18.4.67 | 9.18.4.68 | 9.19.1 | 9.19.1.5 | 9.19.1.9 | 9.19.1.12 | 9.19.1.18 | 9.19.1.22 | 9.19.1.24 | 9.19.1.27 | 9.19.1.28 | 9.19.1.31 | 9.19.1.37 | 9.19.1.38 | 9.19.1.42 | 9.20.1 | 9.20.1.5 | 9.20.2 | 9.20.2.10 | 9.20.2.21 | 9.20.2.22 | 9.20.3 | 9.20.3.4 | 9.20.3.7 | 9.20.3.9 | 9.20.3.10 | 9.20.3.13 | 9.20.3.16 | 9.20.3.20 | 9.20.4 | 9.20.4.7 | 9.20.4.10 | 9.20.4.14 | 9.22.1.1 | 9.22.1.3 | 9.22.1.2 | 9.22.1.6 | 9.22.2 | 9.22.2.4 | 9.22.2.9 | 9.22.2.13 | 9.22.2.14 | 9.23.1 | 9.23.1.3 | 9.23.1.7 | 9.23.1.13 | 9.23.1.19 | 9.23.1.22
  • cisco secure firewall threat defense (ftd) software6.4.0 | 6.4.0.1 | 6.4.0.3 | 6.4.0.2 | 6.4.0.4 | 6.4.0.5 | 6.4.0.6 | 6.4.0.7 | 6.4.0.8 | 6.4.0.9 | 6.4.0.10 | 6.4.0.11 | 6.4.0.12 | 6.4.0.13 | 6.4.0.14 | 6.4.0.15 | 6.4.0.16 | 6.4.0.17 | 6.4.0.18 | 7.0.0 | 7.0.0.1 | 7.0.1 | 7.0.1.1 | 7.0.2 | 7.0.2.1 | 7.0.3 | 7.0.4 | 7.0.5 | 7.0.6 | 7.0.6.1 | 7.0.6.2 | 7.0.6.3 | 7.0.7 | 7.0.8 | 7.0.8.1 | 7.1.0 | 7.1.0.1 | 7.1.0.2 | 7.1.0.3 | 7.2.0 | 7.2.0.1 | 7.2.1 | 7.2.2 | 7.2.3 | 7.2.4 | 7.2.4.1 | 7.2.5 | 7.2.5.1 | 7.2.6 | 7.2.7 | 7.2.5.2 | 7.2.8 | 7.2.8.1 | 7.2.9 | 7.2.10 | 7.2.10.2 | 7.3.0 | 7.3.1 | 7.3.1.1 | 7.3.1.2 | 7.4.0 | 7.4.1 | 7.4.1.1 | 7.4.2 | 7.4.2.1 | 7.4.2.2 | 7.4.2.3 | 7.4.2.4 | 7.4.3 | 7.6.0 | 7.6.1 | 7.6.2 | 7.6.2.1 | 7.7.0 | 7.7.10 | 7.7.10.1
  • secure_firewall_threat_defense6.4.0 | 6.4.0.1 | 6.4.0.2 | 6.4.0.3 | 6.4.0.4 | 6.4.0.5 | 6.4.0.6 | 6.4.0.7 | 6.4.0.8 | 6.4.0.9 | 6.4.0.10 | 6.4.0.11 | 6.4.0.12 | 6.4.0.13 | 6.4.0.14 | 6.4.0.15 | 6.4.0.16 | 6.4.0.17 | 6.4.0.18 | 7.0.0 | 7.0.0.1 | 7.0.1 | 7.0.1.1 | 7.0.2 | 7.0.2.1 | 7.0.3 | 7.0.4 | 7.0.5 | 7.0.6 | 7.0.6.1 | 7.0.6.2 | 7.0.6.3 | 7.0.7 | 7.0.8 | 7.0.8.1 | 7.1.0 | 7.1.0.1 | 7.1.0.2 | 7.1.0.3 | 7.2.0 | 7.2.0.1 | 7.2.1 | 7.2.2 | 7.2.3 | 7.2.4 | 7.2.4.1 | 7.2.5 | 7.2.5.1 | 7.2.5.2 | 7.2.6 | 7.2.7 | 7.2.8 | 7.2.8.1 | 7.2.9 | 7.2.10 | 7.2.10.2 | 7.3.0 | 7.3.1 | 7.3.1.1 | 7.3.1.2 | 7.4.0 | 7.4.1 | 7.4.1.1 | 7.4.2 | 7.4.2.1 | 7.4.2.2 | 7.4.2.3 | 7.4.2.4 | 7.4.3 | 7.6.0 | 7.6.1 | 7.6.2 | 7.6.2.1 | 7.7.0 | 7.7.10 | 7.7.10.1

1 vendor · 4 products

References

1 links