{"id":"CVE-2025-20333","kind":"vulnerability","aliases":["CVE-2025-20333"],"related":[],"title":"A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco…","description":"Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Software VPN Web Server contain a buffer overflow vulnerability that allows for remote code execution. This vulnerability could be chained with CVE-2025-20362.\n\nCISA 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.","summary":"Cisco ASA and Secure Firewall Threat Defense VPN web server has a buffer overflow that allows remote code execution. The sources say it is being exploited in the wild and can be chained with CVE-2025-20362.","severity":"critical","cvss":9.9,"epss":null,"exploited":true,"exploited_at":"2025-09-25T00:00:00+00:00","products":[{"name":"Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":["9.12.4.72"],"affected":">= 9.12, < 9.12.4.72","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":["9.14.4.28"],"affected":">= 9.14, < 9.14.4.28","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":["9.16.4.85"],"affected":">= 9.16, < 9.16.4.85","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":["9.17.1.45"],"affected":">= 9.17.0, < 9.17.1.45","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":["9.18.4.47"],"affected":">= 9.18, < 9.18.4.47","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":["9.19.1.37"],"affected":">= 9.19, < 9.19.1.37","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":["9.20.3.7"],"affected":">= 9.20, < 9.20.3.7","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":["9.22.1.3"],"affected":">= 9.22, < 9.22.1.3","ecosystem":"vendor"},{"name":"cisco secure firewall threat defense","fixed":["7.0.8.1"],"affected":">= 7.0.0, < 7.0.8.1","ecosystem":"vendor"},{"name":"cisco secure firewall threat defense","fixed":["7.2.9"],"affected":">= 7.1.0, < 7.2.9","ecosystem":"vendor"},{"name":"cisco secure firewall threat defense","fixed":["7.4.2.4"],"affected":">= 7.3.0, < 7.4.2.4","ecosystem":"vendor"},{"name":"cisco secure firewall threat defense","fixed":[],"affected":"= 7.6.0","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["asa","cisco","exploited","firewall","ftd","infrastructure","vpn"],"not_affected_if":["no-vpn-web-server"],"how_to_check":null,"fix":null,"status":"open","published_at":"2025-09-25T00:00:00+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:44:49+00:00","updated_at":"2026-10-23T23:44:51+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-23T20:44:49Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"internet","summary":"Cisco ASA and Secure Firewall Threat Defense VPN web server has a buffer overflow that allows remote code execution. The sources say it is being exploited in the wild and can be chained with CVE-2025-20362.","category":"infrastructure","who_cares":["cisco","asa","ftd","firewall","vpn"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Remote attacker runs code on the firewall appliance","analyst_note":"Find Cisco's advisory and CISA ED 25-03 guidance for affected versions, fixed releases and the VPN web server check; sources here give no versions.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["no-vpn-web-server"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.000434,"input_tokens":2776,"output_tokens":313,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-01':242C '-03':207C '-2025':20A,23A,138B,175C '-20333':21A,24A '-20362':139B,176C '22':241C '25':206C 'action':179C 'adapt':12A,143C 'adaptive':28A,37A,42A,47A,52A,57A,62A,67A,72A 'adher':236C 'agenc':191C,213C 'allow':118B,163C 'and':31A 'applianc':14A,146C 'appliance':30A,39A,44A,49A,54A,59A,64A,69A,74A 'applic':239C 'asa':15A,96B,104B,145C 'avail':257C 'begin':197C 'bod':240C 'buffer':115B,159C 'chain':135B,172C 'cisa':177C,221C 'cisco':9A,18A,25A,36A,41A,46A,51A,56A,61A,66A,71A,76A,81A,86A,91A,97B,103B,140C 'cloud':245C 'code':120B,166C 'contain':157C 'could':170C 'cve':19A,22A,137B,174C 'date':183C 'deadlin':187C 'defens':109B,151C 'defense':35A,80A,85A,90A,95A 'direct':204C 'discontinu':248C 'due':182C 'ed':205C 'emerg':203C 'execut':121B,167C 'expect':193C 'exploit':98B,128B 'fceb':190C 'firewal':11A,99B,107B,142C,149C 'firewall':27A,33A,78A,83A,88A,93A 'follow':215C 'ftd':100B,152C 'guidanc':200C,243C 'implement':198C 'infrastructur':101B 'instruct':230C 'kev':181C 'list':209C,223C,232C 'mitig':217C,254C 'must':214C 'note':212C,226C,235C 'outlin':201C 'overflow':116B,160C 'product':252C 'provid':219C 'refer':184C 'remot':119B,165C 'requir':178C 'review':195C 'say':124B 'secur':10A,13A,106B,141C,144C,148C 'secure':26A,32A,77A,82A,87A,92A 'security':29A,38A,43A,48A,53A,58A,63A,68A,73A 'server':7A,112B,156C 'servic':246C 'softwar':16A,153C 'software':40A,45A,50A,55A,60A,65A,70A,75A 'sourc':123B 'step':218C 'threat':34A,79A,84A,89A,94A,108B,150C 'url':208C,222C,231C 'use':249C 'vendor':228C 'vpn':5A,102B,110B,154C 'vulner':2A,161C,169C 'web':6A,111B,155C 'wild':131B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2025-09-25T00:00:00+00:00","kev":{"dateAdded":"2025-09-25","dueDate":"2025-09-26","requiredAction":"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.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cvss_by":"psirt@cisco.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2025-20333","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2025-20333","severity":null,"published_at":"2025-09-25T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T14:39:38+00:00","note":null},{"source":"nvd","external_id":"CVE-2025-20333","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-20333","severity":null,"published_at":"2025-09-25T16:15:32+00:00","modified_at":"2026-10-18T21:10:00+00:00","first_seen_at":"2026-10-23T23:44:51+00:00","fetched_at":"2026-10-23T23:44:51+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}