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CVE-2025-20362

high

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. 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.

From the Tenable Blog

CVE-2025-20333, CVE-2025-20362: Cisco Zero-Days Exploited | Tenable®
CVE-2025-20333, CVE-2025-20362: Cisco Zero-Days Exploited | Tenable®

Published: 2025-09-25

Cisco patched two zero-days in ASA and FTD, CVE-2025-20333, CVE-2025-20362, that were exploited by the same threat actor behind the ArcaneDoor campaign, UAT4356

References

https://www.bleepingcomputer.com/news/security/cisco-actively-exploited-firewall-flaws-now-abused-for-dos-attacks/

https://securityaffairs.com/184321/security/cisco-fixes-critical-uccx-flaw-allowing-root-command-execution.html

https://www.theregister.com/2025/11/06/cisco_firewall_ongoing_attacks/

https://www.securityweek.com/cisco-patches-critical-vulnerabilities-in-contact-center-appliance/

https://www.bleepingcomputer.com/news/security/critical-cisco-uccx-flaw-lets-hackers-run-commands-as-root/

https://thehackernews.com/2025/11/cisco-warns-of-new-firewall-attack.html

https://securityaffairs.com/184290/security/cisco-became-aware-of-a-new-attack-variant-against-secure-firewall-asa-and-ftd-devices.html

https://therecord.media/chinese-hackers-scan-exploit-firewalls-government

https://www.securityweek.com/cisco-fortinet-palo-alto-networks-devices-targeted-in-coordinated-campaign/

https://www.helpnetsecurity.com/2025/10/01/too-many-cisco-asa-firewalls-still-unsecure-despite-zero-day-attack-alerts/

https://www.theregister.com/2025/09/30/cisco_firewall_vulns/

https://www.bleepingcomputer.com/news/security/nearly-50-000-cisco-firewalls-vulnerable-to-actively-exploited-flaws/

https://www.zscaler.com/blogs/security-research/cisco-firewall-and-vpn-zero-day-attacks-cve-2025-20333-and-cve-2025-20362

https://www.theregister.com/2025/09/26/cisco_firewall_flaws/

https://www.securityweek.com/cisco-firewall-zero-days-exploited-in-china-linked-arcanedoor-attacks/

https://www.infosecurity-magazine.com/news/arcanedoor-attacks-against-cisco/

https://www.helpnetsecurity.com/2025/09/26/cisco-asa-zero-day-attacks/

https://unit42.paloaltonetworks.com/zero-day-vulnerabilities-affect-cisco-software/

https://thehackernews.com/2025/09/cisco-asa-firewall-zero-day-exploits.html

https://securityaffairs.com/182639/hacking/uk-ncsc-warns-that-attackers-exploited-cisco-firewall-zero-days-to-deploy-rayinitiator-and-line-viper-malware.html

https://www.darkreading.com/vulnerabilities-threats/cisco-actively-exploited-zero-day-bugs-firewalls-ios

https://www.bleepingcomputer.com/news/security/cisco-warns-of-asa-firewall-zero-days-exploited-in-attacks/

https://www.bleepingcomputer.com/news/security/cisa-orders-agencies-to-patch-cisco-flaws-exploited-in-zero-day-attacks/

https://therecord.media/cisco-asa-firewall-bugs-cisa-federal-agencies-warning

https://thehackernews.com/2025/09/urgent-cisco-asa-zero-day-duo-under.html

https://securityaffairs.com/182593/hacking/u-s-cisa-adds-cisco-secure-firewall-asa-and-secure-ftd-flaws-to-its-known-exploited-vulnerabilities-catalog.html

https://sec.cloudapps.cisco.com/security/center/resources/asa_ftd_continued_attacks

https://cyberscoop.com/cisa-emergency-directive-cisco-zero-days/

https://www.tenable.com/blog/cve-2025-20333-cve-2025-20362-faq-cisco-asa-ftd-zero-days-uat4356

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20362

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-webvpn-YROOTUW

Details

Source: Mitre, NVD

Published: 2025-09-25

Updated: 2025-11-06

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 9

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:C

Severity: High

CVSS v3

Base Score: 8.6

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

Severity: High

EPSS

EPSS: 0.29718

Vulnerability Watch

Tenable Research has classified this CVE under the following Vulnerability Watch classification, which includes active and historical (inactive) classifications. You can learn more about these classifications on our blog.

Vulnerability of Interest