{"id":"CVE-2024-20353","kind":"vulnerability","aliases":["CVE-2024-20353"],"related":[],"title":"cisco adaptive security appliance software: A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco…","description":"A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.\r\n\r This vulnerability is due to incomplete error checking when parsing an HTTP header. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted web server on a device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.","summary":"Cisco ASA and Firepower Threat Defense firewalls contain an infinite loop bug that an attacker can trigger remotely. Triggering it causes a denial of service, taking the device offline.","severity":"high","cvss":8.6,"epss":null,"exploited":true,"exploited_at":"2024-04-24T00:00:00+00:00","products":[{"name":"Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.1","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.1.5","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.1.7","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.8","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.14","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.15","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.17","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.20","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.24","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.26","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.28","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.33","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.35","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.2.38","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3.8","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3.11","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3.14","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3.16","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3.18","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3.21","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3.26","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.3.29","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.3","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.7","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.8","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.10","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.12","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.15","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.17","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.20","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.22","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.25","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.26","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.29","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.32","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.33","ecosystem":"vendor"},{"name":"cisco adaptive security appliance software","fixed":[],"affected":"= 9.8.4.34","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["cisco-asa","cisco-ftd","exploited","firewall","infrastructure"],"not_affected_if":["unknown"],"how_to_check":null,"fix":"Apply the mitigations in the Cisco advisory; CISA says to discontinue use of the product if mitigations are unavailable. Specific fixed versions: unknown","status":"open","published_at":"2024-04-24T00:00:00+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T21:00:49+00:00","updated_at":"2026-10-23T22:29:05+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-23T21:00:49Z","model":"claude-haiku-5-5","output":{"fix":"Apply the mitigations in the Cisco advisory; CISA says to discontinue use of the product if mitigations are unavailable. Specific fixed versions: unknown","reach":"internet","impact":"low","summary":"Cisco ASA and Firepower Threat Defense firewalls contain an infinite loop bug that an attacker can trigger remotely. Triggering it causes a denial of service, taking the device offline.","category":"infrastructure","who_cares":["cisco-asa","cisco-ftd","firewall"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Remote attacker crashes or hangs the firewall, causing denial of service","analyst_note":"Find the Cisco advisory for CVE-2024-20353 to get affected versions, fixed releases, and the exact trigger conditions for how_to_check and fix.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["unknown"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.00047,"input_tokens":2878,"output_tokens":364,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2024':25A,28A '-20353':26A,29A 'adapt':2A,17A,289C 'adaptive':31A,41A,46A,51A,56A,61A,66A,71A,76A,81A,86A,91A,96A,101A,106A,111A,116A,121A,126A,131A,136A,141A,146A,151A,156A,161A,166A,171A,176A,181A,186A,191A,196A,201A,206A,211A,216A,221A,226A,231A,236A 'allow':302C,359C 'and':35A 'applianc':4A,19A,291C 'appliance':33A,43A,48A,53A,58A,63A,68A,73A,78A,83A,88A,93A,98A,103A,108A,113A,118A,123A,128A,133A,138A,143A,148A,153A,158A,163A,168A,173A,178A,183A,188A,193A,198A,203A,208A,213A,218A,223A,228A,233A,238A 'asa':20A,34A,242B,250B,292C 'attack':263B,306C,336C,361C 'bug':260B 'caus':269B,308C,363C 'check':329C 'cisco':1A,16A,23A,30A,40A,45A,50A,55A,60A,65A,70A,75A,80A,85A,90A,95A,100A,105A,110A,115A,120A,125A,130A,135A,140A,145A,150A,155A,160A,165A,170A,175A,180A,185A,190A,195A,200A,205A,210A,215A,220A,225A,230A,235A,241B,244B,249B,288C,295C 'cisco-asa':240B 'cisco-ftd':243B 'condit':321C,366C 'contain':256B 'could':301C,337C,358C 'craft':344C 'cve':24A,27A 'defens':254B,298C 'defense':38A 'denial':271B,317C 'devic':276B,310C,354C,369C 'dos':320C,365C 'due':325C 'error':328C 'exploit':246B,338C,357C 'firepow':252B,296C 'firepower':36A 'firewal':247B,255B 'ftd':39A,245B,299C 'header':334C 'http':333C,345C 'incomplet':327C 'infinit':258B 'infrastructur':248B 'loop':259B 'manag':10A,282C 'offlin':277B 'pars':331C 'reload':312C,370C 'remot':266B,305C 'request':346C 'result':314C 'secur':3A,18A,290C 'security':32A,42A,47A,52A,57A,62A,67A,72A,77A,82A,87A,92A,97A,102A,107A,112A,117A,122A,127A,132A,137A,142A,147A,152A,157A,162A,167A,172A,177A,182A,187A,192A,197A,202A,207A,212A,217A,222A,227A,232A,237A 'send':342C 'server':14A,286C,351C 'servic':273B,319C 'softwar':5A,21A,293C,300C 'software':44A,49A,54A,59A,64A,69A,74A,79A,84A,89A,94A,99A,104A,109A,114A,119A,124A,129A,134A,139A,144A,149A,154A,159A,164A,169A,174A,179A,184A,189A,194A,199A,204A,209A,214A,219A,224A,229A,234A,239A 'success':356C 'take':274B 'target':349C 'threat':37A,253B,297C 'trigger':265B,267B 'unauthent':304C 'unexpect':313C 'vpn':12A,284C 'vulner':7A,279C,323C,340C 'web':13A,285C,350C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2024-04-24T00:00:00+00:00","kev":{"dateAdded":"2024-04-24","dueDate":"2024-05-01","requiredAction":"Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","cvss_by":"psirt@cisco.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2024-20353","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2024-20353","severity":null,"published_at":"2024-04-24T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T11:39:15+00:00","note":null},{"source":"nvd","external_id":"CVE-2024-20353","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-20353","severity":null,"published_at":"2024-04-24T19:15:46+00:00","modified_at":"2026-08-11T19:33:44+00:00","first_seen_at":"2026-10-23T22:29:05+00:00","fetched_at":"2026-10-23T22:29:05+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"}