Cisco ASA/Firepower Threat Defense Software DHCP Client memory leak

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.2$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic has been found in Cisco ASA and Firepower Threat Defense Software. Impacted is an unknown function of the component DHCP Client. Performing a manipulation results in memory leak. This vulnerability was named CVE-2025-20135. The attack needs to be approached within the local network. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in Cisco ASA and Firepower Threat Defense Software (version now known). This affects some unknown processing of the component DHCP Client. The manipulation with an unknown input leads to a memory leak vulnerability. CWE is classifying the issue as CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. This is going to have an impact on availability. The summary by CVE is:

A vulnerability in the DHCP client functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to exhaust available memory. This vulnerability is due to improper validation of incoming DHCP packets. An attacker could exploit this vulnerability by repeatedly sending crafted DHCPv4 packets to an affected device. A successful exploit could allow the attacker to exhaust available memory, which would affect availability of services and prevent new processes from starting, resulting in a Denial of Service (DoS) condition that would require a manual reboot. Note: On Cisco Secure FTD Software, this vulnerability does not affect management interfaces.

The advisory is shared at sec.cloudapps.cisco.com. This vulnerability is uniquely identified as CVE-2025-20135 since 10/10/2024. The exploitability is told to be easy. Access to the local network is required for this attack to succeed. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/17/2025).

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2025-1839). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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: 4.3
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.3
CNA Vector (cisco): 🔒

CVSSv2info

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

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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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
08/17/2025 +3 days VulDB entry last update

Sourcesinfo

Vendor: cisco.com

Advisory: cisco-sa-asaftd-dhcp-qj7nGs4N
Status: Confirmed

CVE: CVE-2025-20135 (🔒)
GCVE (CVE): GCVE-0-2025-20135
GCVE (VulDB): GCVE-100-320193
CERT Bund: WID-SEC-2025-1839 - Cisco ASA und Secure Firewall Threat Defense: Mehrere Schwachstellen

Entryinfo

Created: 08/14/2025 19:49
Updated: 08/17/2025 07:29
Changes: 08/14/2025 19:49 (64), 08/17/2025 07:29 (7)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

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