Cisco ASA/Firepower Threat Defense Software SSL VPN Service improper validation of specified type of input

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.9$0-$5k0.00

Summaryinfo

A vulnerability was found in Cisco ASA and Firepower Threat Defense Software. It has been declared as critical. This impacts an unknown function of the component SSL VPN Service. Such manipulation leads to improper validation of specified type of input. This vulnerability is documented as CVE-2025-20244. The attack can be executed remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Cisco ASA and Firepower Threat Defense Software (version now known). Affected by this issue is some unknown processing of the component SSL VPN Service. The manipulation with an unknown input leads to a improper validation of specified type of input vulnerability. Using CWE to declare the problem leads to CWE-1287. The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type. Impacted is availability. CVE summarizes:

A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow a remote attacker that is authenticated as a VPN user 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 field value. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause a DoS condition, which would cause the affected device to reload.

The advisory is available at sec.cloudapps.cisco.com. This vulnerability is handled as CVE-2025-20244 since 10/10/2024. The exploitation is known to be easy. The attack may be launched remotely. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/26/2025).

The vulnerability scanner Nessus provides a plugin with the ID 255229 (Cisco Secure Firewall Threat Defense Remote Access VPN Web Server DoS (cisco-sa-asaftd-vpnwebs-dos-hjBhmBsX)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (255229) and CERT Bund (WID-SEC-2025-1839). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Cisco ASA (Adaptive Security Appliance)

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.1
VulDB Meta Temp Score: 6.9

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.7
CNA Vector (cisco): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper validation of specified type of input
CWE: CWE-1287 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 255229
Nessus Name: Cisco Secure Firewall Threat Defense Remote Access VPN Web Server DoS (cisco-sa-asaftd-vpnwebs-dos-hjBhmBsX)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

10/10/2024 CVE reserved
08/14/2025 +308 days Advisory disclosed
08/14/2025 +0 days VulDB entry created
08/26/2025 +12 days VulDB entry last update

Sourcesinfo

Vendor: cisco.com

Advisory: cisco-sa-asaftd-vpnwebs-dos-hjBhmBsX
Status: Confirmed

CVE: CVE-2025-20244 (🔒)
GCVE (CVE): GCVE-0-2025-20244
GCVE (VulDB): GCVE-100-320186
CERT Bund: WID-SEC-2025-1839 - Cisco ASA und Secure Firewall Threat Defense: Mehrere Schwachstellen

Entryinfo

Created: 08/14/2025 19:47
Updated: 08/26/2025 22:05
Changes: 08/14/2025 19:47 (63), 08/17/2025 08:31 (7), 08/26/2025 22:05 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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