CVE-2025-20362: Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Missing Authorization Vulnerability

What it is

Update: On November 5, 2025, Cisco became aware of a new attack variant against devices running Cisco Secure ASA Software or Cisco Secure FTD Software releases that are affected by CVE-2025-20333 and CVE-2025-20362. This attack can cause unpatched devices to unexpectedly reload, leading to denial of service (DoS) conditions. Cisco strongly recommends that all customers upgrade to the fixed software releases that are listed in the Fixed Software [“#fs”] section of this advisory. A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to access restricted URL endpoints that are related to remote access VPN that should otherwise be inaccessible without authentication. This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web server on a device. A successful exploit could allow the attacker to access a restricted URL without authentication.

Description quoted from the CVE record (assigned by cisco, published 2025-09-25).

Weakness: Missing Authorization

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality low, integrity low, availability none. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: partial.

On CISA KEV since

2025-09-25

US federal deadline

2025-09-26

Ransomware use

Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2025-11751, CNNVD-202509-3957, EUVD-2025-31139, GHSA-wx28-57x9-xv5f

VEDAS cluster: VEDAS:FLINTFIREBREATH

Exploit Observer links 7 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (7)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

• Nuclei template: https://raw.githubusercontent.com/projectdiscovery/nuclei-templates/main/http/cves/2025/CVE-2025-20362.yaml
• Code repository: https://github.com/curtishoughton/cve-2025-20362-cisco-scanner
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/nuclei/2025/CVE-2025-20362.yaml
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/nuclei/2025/CVE-2025-20362.yaml
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2025/CVE-2025-20362.rules
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2025/CVE-2025-20362.rules
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2025/CVE-2025-20362.rules

Research and write-ups (3)

• Research or write-up: https://attackerkb.com/topics/Szq5u0xgUX/cve-2025-20362/rapid7-analysis
• Research or write-up: https://ptsecurity.com/research/trending-vulnerabilities/CVE-2025-20362
• Research or write-up: https://ptsecurity.com/ru-ru/research/trending-vulnerabilities/CVE-2025-20362

Vulnerability databases and vendor advisories (6)

Catalogue entries, not exploit evidence.

• Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2025-31139
• Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-wx28-57x9-xv5f
• Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2025-20362
• Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20362
• Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-202509-3957
• Vulnerability database or vendor advisory: https://www.tenable.com/cve/CVE-2025-20362

45 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS

0.871
very likely to be attacked soon

VEDAS

0.978
strong exploit evidence

On CISA KEV

Yes, since 2025-09-25

Detection rule

Nuclei · Suricata

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish.

Who is affected

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: cisco adaptive_security_appliance_software, cisco secure_firewall_threat_defense, cisco_systems,_inc. adaptive_security_appliance.

How to fix it

CISA required action: The KEV due date refers to the deadline by which FCEB agencies are expected to review and begin implementing the guidance outlined in Emergency Directive (ED) 25-03 (URL listed below in Notes). Agencies must follow the mitigation steps provided by CISA (URL listed below in Notes) and vendor’s instructions (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.

Vendor guidance:

• https://sec.cloudapps.cisco.com/security/center/resources/asa_ftd_continued_attacks (vendor-advisory)

How to detect it

Nuclei template (active check)

Cisco ASA - Missing Authorization

Update: On November 5, 2025, Cisco became aware of a new attack variant against devices running Cisco Secure ASA Software or Cisco Secure FTD Software releases that are affected by CVE-2025-20333 and CVE-2025-20362. This attack can cause unpatched devices to unexpectedly reload, leading to denial of service (DoS) conditions.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (POST /+CSCOU+//../+CSCOE+/files/file_action.html?mode=upload&path=foo&se...); it decides using status, word matchers. Severity in the template: medium. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

nuclei -u https://your-host -t CVE-2025-20362.yaml

id: CVE-2025-20362

info:
  name: "Cisco ASA - Missing Authorization"
  author: vedas-arpsyndicate
  severity: medium
  description: |
    Update: On November 5, 2025, Cisco became aware of a new attack variant against devices running Cisco Secure
    ASA Software or Cisco Secure FTD Software releases that are affected by CVE-2025-20333 and CVE-2025-20362.
    This attack can cause unpatched devices to unexpectedly reload, leading to denial of service (DoS) conditions.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2025-20362&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=cisco&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
    cvss-score: 6.5
    cve-id: CVE-2025-20362
    cwe-id: CWE-862
  metadata:
    verified: false
  tags: cve,cve2025,cisco,asa,auth-bypass,kev,vkev,vuln
http:
  - raw:
      - |
        POST /+CSCOU+//../+CSCOE+/files/file_action.html?mode=upload&path=foo&server=srv&sourceurl=qaz HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded;boundary=ee
        Content-Length: 10

        aabbccdd

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - "<script>alert('CSRF token mismatch')"
          - "Failed to upload file"

      - type: status
        status:
          - 200

CVE-2025-20362.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2025-20362 Cisco ASA - Missing Authorization. Add them to your Suricata rule set and reload.

alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2025-20362 Cisco ASA - Missing Authorization"; flow:established,to_server; http.uri; content:"file_action.html"; nocase; content:"../"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2025-20362; reference:url,https://www.exploit.observer/?keyword=CVE-2025-20362&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=cisco&match=exact; sid:1009082; rev:1;)

CVE-2025-20362.rules on GitHub

Advisories on this CVE

• Cisco ASA / FTD zero-days, ArcaneDoor (CVE-2025-20333 / -20362) (25 Sep 2025)

References

Vendor advisories and patches

• https://sec.cloudapps.cisco.com/security/center/resources/asa_ftd_continued_attacks (vendor-advisory)

Government sources

• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20362 (government-resource)

Other references

• cisco-sa-asaftd-webvpn-YROOTUW

Other databases

• CVE record (cve.org)
• NVD
• Exploit Observer

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.