CVE-2024-20353
Exploited in the wild. In CISA KEV since 2024‑04‑24. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Listed as exploited in the wild since 2024-04-24.
US federal agencies must remediate by 2024-05-01.
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- Public exploits
1 source with a proof of concept or module.
Exploit links, PoCs and Metasploit modules after sign-in- EPSS
71% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
The patch came 129 days before any public exploit.
- Analysis publishedThe Firewall Crash Bug Cisco Has Now Shipped Twice: CVE-2026-20349 and Its 2024 Twin
- Patch availablerecord updated
- OpenVAS check added
- EPSS band changemoderate → high
- Public exploit / PoCsource: other
- Patch availablerecord updated
Affected products
- adaptive security appliance softwareNetworking Infrastructure
- secure firewall threat defenseNetworking Infrastructure / router-switch
- Firepower Threat DefenseNetworking Infrastructure
- Adaptive Security ApplianceNetworking Infrastructure
- Cisco Adaptive Security Appliance (ASA) SoftwareNetworking Infrastructure
- Cisco Firepower Threat Defense SoftwareNetworking Infrastructure
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Scored 8.6 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
Sources
References in the record
- sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-websrvs-dos-X8gNucD2
- blog.talosintelligence.com/arcanedoor-new-espionage-focused-campaign-found-targeting-perimeter-network-devices/
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-20353
And 3 more references. See all after sign-in
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