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CVE-2020-3529 Cisco Adaptive Security Appliance

Affected softwareCisco Adaptive Security Appliance
Severity8.6 High CVSS 3.1 3 scores
WeaknessUncontrolled resource consumption (CWE-400)
Published21 Oct 2020
Updated11 Aug 2026

Description

A vulnerability in the SSL VPN negotiation process for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to inefficient direct memory access (DMA) memory management during the negotiation phase of an SSL VPN connection. An attacker could exploit this vulnerability by sending a steady stream of crafted Datagram TLS (DTLS) traffic to an affected device. A successful exploit could allow the attacker to exhaust DMA memory on the device and cause a DoS condition.

Exploitation status

Exploited

Real-world exploitation reported by VulnCheck KEV. CISA has not confirmed it.
  • CISA KEV not listed
  • VulnCheck KEV listed Exploitation reported in the wild. 1 citation · earliest 2025-04-23.
  • CISA Vulnrichment no assessment published
  • Indexed PoC none indexed
  • EPSS 1.8% chance in 30 days

VulnCheck KEV

Exploitation evidence from VulnCheck Known Exploited Vulnerabilities (VulnCheck KEV), used under VulnCheck's community terms. View CVE-2020-3529 in VulnCheck (free account).

EvidenceSourceDetailDate
Reported exploitation services.google.com /fh/files/misc/m-trends-2025-en.pdf 2025-04-23

Waratek protection

Outside Waratek scope

A Java vulnerability, but not one Waratek protects. It affects only Java on a user's desktop (applets, Web Start, JavaFX, the installer), sits in a product the Waratek agent can't be installed into, or is in a package we don't expect in business applications. The decision below says which.

  • Protection none
  • Action not pursued none
  • Review human Researcher
  • Record active
Decided by Manual classification of this CVE in the legacy dataset
Finding A manual classification set this CVE's status to Outside Waratek scope, but the CVE names a tracked product.

CVSS

8.6 HIGH v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H 3 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 8.6 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H psirt@cisco.com Secondary published
CVSS 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H NVD Primary
CVSS 2.0 5.0 none AV:N/AC:L/Au:N/C:N/I:N/A:P NVD Primary

Affected software and releases

Products and versions

3 products, 11 version entries
SourceVendorProductSchemeAffected versions
nvd cisco adaptive security appliance generic ＜ 9.6.4.45
nvd cisco adaptive security appliance software generic ≥ 9.8.0 and ＜ 9.8.4.29 · ≥ 9.9.0 and ＜ 9.9.2.80 · ≥ 9.10.0 and ＜ 9.10.1.44 · ≥ 9.12.0 and ＜ 9.12.4.4 · ≥ 9.13.0 and ＜ 9.13.1.13 · ≥ 9.14.0 and ＜ 9.14.1.30
nvd cisco secure firewall threat defense generic ＜ 6.3.0.6 · ≥ 6.4.0 and ＜ 6.4.0.10 · ≥ 6.5.0 and ＜ 6.5.0.5 · ≥ 6.6.0 and ＜ 6.6.1

References

URLTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-sslvpndma-dos-HRrqB9Yx Vendor Advisory

Timeline
Published2020-10-21By the CVE Program.
VulnCheck KEV: earliest evidence2025-04-23Date of the oldest evidence of exploitation in VulnCheck KEV's record. VulnCheck does not publish the date it listed the CVE.
NVD record modified2026-08-11NVD's own last-modified date for this record.