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CVE-2025-20135· NVD / CVE Program· CNA cisco

Cisco Adaptive Security Appliance and Firepower Threat Defense Software DHCP Denial of Service Vulnerability

Noroxi assessment

Priority: Monitor (action score 17/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.19% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 4.3 · v3.1—No exploit No fix recorded
Published
Aug 14, 2025
Updated
Jun 17, 2026
EPSS
0.1% · 9th percentile

Report tools

JSON

Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · cisco
4.3
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-20135

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.

  • Cisco Cisco Adaptive Security Appliance (ASA) Software

    • 9.12.3, 9.8.3, 9.12.1, 9.8.1, 9.12.2, 9.8.2.45, 9.8.2, 9.8.4, 9.14.1, 9.12.4, 9.8.2.26, 9.8.2.24 … (+28)affected
  • Cisco Cisco Firepower Threat Defense Software

    • 6.2.3.14, 6.4.0.1, 6.2.3.7, 6.2.3, 6.4.0.2, 6.2.3.9, 6.2.3.1, 6.2.3.2, 6.4.0.5, 6.2.3.10, 6.4.0, 6.4.0.3 … (+28)affected

Other highest-scoring records for the same primary product.

  • CVE-2025-20263Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Buffer Overflow Denial of Service Vulnerability
    34Monitor
  • CVE-2025-20253Cisco IOS, IOS XE, Secure Firewall Adaptive Security Appliance, and Secure Firewall Threat Defense Software IKEv2 Denial of Service Vulnerability
    34Monitor
  • CVE-2025-20251Cisco Secure Firewall Adaptive Security Appliance and Cisco Secure Firewall Threat Defense Software Authenticated Arbitrary File Deletion
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-20133Aug 14, 2025 · Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Authentication Targeted Denial of Service Vu
    34Monitor
  • ← EarlierCVE-2025-20134Aug 14, 2025 · Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL/TLS Certificate Denial of Service Vulnerability
    34Monitor
  • Later →CVE-2025-20136Aug 14, 2025 · Cisco Adaptive Security Appliance and Firepower Threat Defense Software Network Address Translation DNS Inspection Denial of Service Vulnerability
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-201330 days apartCisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Authentication Targeted Denial of Service Vu
    34Monitor
  • CVE-2025-202520 days apartA vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software an
    23Monitor
  • CVE-2025-202540 days apartA vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software an
    23Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
low · the service can be disrupted
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
Low

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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