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CVE-2024-20331

Cisco Adaptive Security Appliance and Firepower Threat Defense Software VPN Authentication DoS Vulnerability

Description

A vulnerability in the session authentication functionality of the Remote Access SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to prevent users from authenticating. This vulnerability is due to insufficient entropy in the authentication process. An attacker could exploit this vulnerability by determining the handle of an authenticating user and using it to terminate their authentication session. A successful exploit could allow the attacker to force a user to restart the authentication process, preventing a legitimate user from establishing remote access VPN sessions.

Timeline

  1. ID reserved

    By cisco

  2. · 12 months later

    Published

  3. · 1 day later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2024-20331, by who scored it
Scored byCVSSScoreVector
ciscoCNA (assigner)3.1Medium6.8CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
NVDNVD · Analyzed3.1Medium5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
0.68% · top 47% of all CVEs (10 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: no · Technical impact: partial
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.8.

Affected products

  • Cisco · Cisco Adaptive Security Appliance (ASA) Software

    • affected 9.12.3
    • affected 9.8.3
    • affected 9.12.1
    • affected 9.8.1
    • affected 9.12.2
    • affected 9.8.2.45
    • affected 9.8.2
    • affected 9.8.4
    • affected 9.14.1
    • affected 9.12.4
    • affected 9.8.2.26
    • affected 9.8.2.24
    • affected 9.8.2.15
    • affected 9.8.2.14
    • affected 9.8.2.35
    • affected 9.8.2.20
    • affected 9.8.2.8
    • affected 9.8.2.17
    • affected 9.8.2.28
    • affected 9.8.2.33
    • affected 9.8.2.38
    • affected 9.8.4.25
    • affected 9.12.3.2
    • affected 9.12.3.7
    • affected 9.8.3.18
    • affected 9.8.3.14
    • affected 9.8.4.15
    • affected 9.8.4.8
    • affected 9.8.1.7
    • affected 9.8.3.29
    • affected 9.14.1.10
    • affected 9.12.2.5
    • affected 9.8.4.22
    • affected 9.12.3.12
    • affected 9.8.4.7
    • affected 9.8.4.17
    • affected 9.8.3.16
    • affected 9.8.4.20
    • affected 9.8.3.11
    • affected 9.12.1.3
    • and 148 more

  • Cisco · Cisco Firepower Threat Defense Software

    • affected 6.2.3.14
    • affected 6.4.0.1
    • affected 6.2.3.7
    • affected 6.2.3
    • affected 6.4.0.2
    • affected 6.2.3.9
    • affected 6.2.3.1
    • affected 6.2.3.2
    • affected 6.4.0.5
    • affected 6.2.3.10
    • affected 6.4.0
    • affected 6.4.0.3
    • affected 6.2.3.6
    • affected 6.4.0.4
    • affected 6.2.3.15
    • affected 6.2.3.5
    • affected 6.2.3.4
    • affected 6.2.3.3
    • affected 6.2.3.8
    • affected 6.4.0.6
    • affected 6.2.3.11
    • affected 6.2.3.12
    • affected 6.2.3.13
    • affected 6.4.0.7
    • affected 6.4.0.8
    • affected 6.6.0
    • affected 6.4.0.9
    • affected 6.2.3.16
    • affected 6.6.0.1
    • affected 6.6.1
    • affected 6.4.0.10
    • affected 6.7.0
    • affected 6.4.0.11
    • affected 6.6.3
    • affected 6.7.0.1
    • affected 6.6.4
    • affected 6.4.0.12
    • affected 6.7.0.2
    • affected 7.0.0
    • affected 6.2.3.17
    • and 44 more

What to do

Exploitation: The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

References

3

Sources

The same CVE in the primary databases and aggregators, to check against.

Badge for a README or a ticket

CVE-2024-20331 badge
[![CVE-2024-20331](https://cveledger.app/badge/CVE-2024-20331.svg)](https://cveledger.app/cve/CVE-2024-20331)

Record last updated .