A vulnerability in the processing of Galois/Counter Mode (GCM)-encrypted Internet Key Exchange version 2 (IKEv2) IPsec traffic of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to the allocation of an insufficiently sized block of memory. An attacker could exploit this vulnerability by sending crafted GCM-encrypted IPsec traffic to an affected device. A successful exploit could allow the attacker to cause an unexpected reload of the device, resulting in a DoS condition. To exploit this vulnerability, the attacker must have valid credentials to establish a VPN connection with the affected device.
CVE-2026-20049
Score 7.7 from GitHub Security Advisory (severity: HIGH) published 2026-03-04. NVD baseline CVSS 7.7; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.7
- EG Score
- 7.7(medium)
- EPSS
- 21.4%
- KEV
- Not listed
Published
March 4, 2026
Last Modified
April 16, 2026
Advisory Details (1)
Auto-updated Jun 10, 2026Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software IPsec Denial of Service Vulnerability
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-esp-dos-uv7yD8P5Vendor Advisories for CVE-2026-20049(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 12× in last 7d / 41× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 112 total refreshes for this CVE.
- 2026-07-22 14:08 UTCEPSS rescore
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Related CVEs(same CWE)
Same CWE
10 shownCWE-131
- CVE-2022-33211EG 9.8CRITICAL
- CVE-2023-0568NVD 7.5EG 9.8HIGH
- CVE-2021-38435NVD 6.6EG 9.8MEDIUM
- CVE-2021-38423NVD 6.6EG 9.8MEDIUM
- CVE-2021-0254EG 9.8CRITICAL
- CVE-2021-27378EG 9.8CRITICAL
- CVE-2020-15350EG 9.8CRITICAL
- CVE-2019-10500EG 9.8CRITICAL
- CVE-2019-10627EG 9.8CRITICAL
- CVE-2018-14618NVD 7.5EG 9.8EPSS 95%HIGH
Frequently asked(5)
What is CVE-2026-20049?
When was CVE-2026-20049 disclosed?
Is CVE-2026-20049 actively exploited?
What is the CVSS score of CVE-2026-20049?
How do I remediate CVE-2026-20049?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-20049
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