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CVE-2024-20353VulnerabilityPublished Updated

CVE-2024-20353: Cisco Adaptive Security Appliance (ASA) Software · Infinite Loop

Affects Cisco Adaptive Security Appliance (ASA) SoftwareSource CVE Database V5

0

Exploited in the wild · KEV due 1 May 2024 · 69% EPSS : apply the vendor's fix or mitigations to Cisco Adaptive Security Appliance (ASA) Software now.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.
KEV deadline
 US federal agencies must patch by this date; a sensible deadline for everyone else.
EPSS
69.8% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 24 Apr 2024

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: evidence found.

    Listed in CISA KEV the same day as disclosure

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by cisco

    , 168 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. , the same day as disclosure

  4. KEV remediation due

    US federal deadline

    , 7 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

What to do

Affected software

ProductAffectedFixed in
Cisco Cisco Adaptive Security Appliance (ASA) SoftwareAffected
  • =9.8.1
  • =9.8.1.5
  • =9.8.1.7
  • =9.8.2
  • =9.8.2.8
  • =9.8.2.14
  • =9.8.2.15
  • =9.8.2.17
  • =9.8.2.20
  • =9.8.2.24
  • =9.8.2.26
  • =9.8.2.28
  • =9.8.2.33
  • =9.8.2.35
  • =9.8.2.38
  • =9.8.3.8
  • =9.8.3.11
  • =9.8.3.14
  • =9.8.3.16
  • =9.8.3.18
  • =9.8.3.21
  • =9.8.3
  • =9.8.3.26
  • =9.8.3.29
  • =9.8.4
  • =9.8.4.3
  • =9.8.4.7
  • =9.8.4.8
  • =9.8.4.10
  • =9.8.4.12
  • =9.8.4.15
  • =9.8.4.17
  • =9.8.4.25
  • =9.8.4.20
  • =9.8.4.22
  • =9.8.4.26
  • =9.8.4.29
  • =9.8.4.32
  • =9.8.4.33
  • =9.8.4.34
  • =9.8.4.35
  • =9.8.4.39
  • =9.8.4.40
  • =9.8.4.41
  • =9.8.4.43
  • =9.8.4.44
  • =9.8.4.45
  • =9.8.4.46
  • =9.8.4.48
  • =9.12.1
  • =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
  • =9.14.1
  • =9.14.1.10
  • =9.14.1.6
  • =9.14.1.15
  • =9.14.1.19
  • =9.14.1.30
  • =9.14.2
  • =9.14.2.4
  • =9.14.2.8
  • =9.14.2.13
  • =9.14.2.15
  • =9.14.3
  • =9.14.3.1
  • =9.14.3.9
  • =9.14.3.11
  • =9.14.3.13
  • =9.14.3.18
  • =9.14.3.15
  • =9.14.4
  • =9.14.4.6
  • =9.14.4.7
  • =9.14.4.12
  • =9.14.4.13
  • =9.14.4.14
  • =9.14.4.15
  • =9.14.4.17
  • =9.14.4.22
  • =9.14.4.23
  • =9.15.1
  • =9.15.1.7
  • =9.15.1.10
  • =9.15.1.15
  • =9.15.1.16
  • =9.15.1.17
  • =9.15.1.1
  • =9.15.1.21
  • =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
  • =9.16.4.18
  • =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
  • =9.17.1
  • =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
  • =9.18.1
  • =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
  • =9.19.1
  • =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
  • =9.20.1
  • =9.20.1.5
  • =9.20.2
Fixed in–

Check the firmware or software version for Cisco Adaptive Security Appliance (ASA) Software in the device's admin interface against the vendor advisory.

Description

A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to incomplete error checking when parsing an HTTP header. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted web server on a device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.

References

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