{"id":"CVE-2026-76490","kind":"vulnerability","aliases":["CVE-2026-76490"],"related":[],"title":"Cisco Expressway: out-of-bounds write flaws may let attackers run code","description":"As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.  \r\n\r\nThe vulnerabilities tracked by CVE-2026-76490 are related to issues concerning out-of-bounds writes that are grouped under the Common Weakness Enumeration (CWE) Base CWE-787.","summary":"Cisco Expressway Series video gateways contain multiple out-of-bounds write flaws found in an internal security review, classified as CWE-787. The sources do not say what an attacker can do after triggering them, and NVD rates the issue 8.6 (high).","severity":"high","cvss":8.6,"epss":0.00346,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["cisco-expressway","infrastructure","self-hosted","video-conferencing"],"not_affected_if":["unknown"],"how_to_check":"Check the installed Expressway software version in the admin interface under Status or System information and compare it with the fixed releases in Cisco's advisory.","fix":"Upgrade Cisco Expressway to a fixed software release named in Cisco's security advisory; the release number is unknown from these sources.","status":"open","published_at":"2026-10-21T17:19:08+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","triaged_at":"2026-10-23T22:39:22+00:00","updated_at":"2026-10-24T13:15:54+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-10-23T22:39:22Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade Cisco Expressway to a fixed software release named in Cisco's security advisory; the release number is unknown from these sources.","reach":"unknown","title":"Cisco Expressway: out-of-bounds write flaws may let attackers run code","impact":"high","summary":"Cisco Expressway Series video gateways contain multiple out-of-bounds write flaws found in an internal security review, classified as CWE-787. The sources do not say what an attacker can do after triggering them, and NVD rates the issue 8.6 (high).","category":"infrastructure","who_cares":["cisco-expressway","video-conferencing","self-hosted"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown; out-of-bounds writes can allow code execution or crashes","analyst_note":"Find the Cisco advisory for CVE-2026-76490 to get fixed versions, the affected attack surface and whether authentication is required.","how_to_check":"Check the installed Expressway software version in the admin interface under Status or System information and compare it with the fixed releases in Cisco's advisory.","needs_analyst":true,"not_affected_if":["unknown"],"user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000517,"input_tokens":2973,"output_tokens":439,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A,118C '-76490':16A,19A,119C '-787':52B,141C '8.6':71B 'address':108C 'attack':11A,60B 'base':139C 'bound':6A,40B,128C 'cisco':1A,21B,30B,76C,87C 'cisco-expressway':20B 'classifi':49B 'code':13A 'commit':79C 'common':135C 'comprehens':96C 'concern':124C 'conduct':94C 'conferenc':29B 'contain':35B 'cve':14A,17A,117C 'cwe':51B,138C,140C 'discov':111C 'engin':91C 'enumer':137C 'expressway':2A,22B,31B,88C 'flaw':8A,42B 'found':43B 'gateway':34B 'group':132C 'harden':105C 'high':72B 'host':26B 'infrastructur':23B 'intern':46B,97C,110C 'issu':70B,123C 'let':10A 'may':9A 'multipl':36B,109C 'nvd':67B 'ongo':78C 'out-of-bound':3A,37B,125C 'part':74C 'proactiv':81C 'product':84C 'qualiti':85C 'rate':68B 'relat':121C 'releas':106C 'result':102C 'review':48B,99C,101C 'run':12A 'say':57B 'secur':47B,82C,98C 'self':25B 'self-host':24B 'seri':32B,89C 'softwar':90C,104C 'sourc':54B 'team':92C 'track':115C 'trigger':64B 'video':28B,33B 'video-conferenc':27B 'vulner':112C,114C 'weak':136C 'write':7A,41B,129C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-21T17:19:08+00:00","kev":null,"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":"nvd","external_id":"CVE-2026-76490","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-76490","severity":null,"published_at":"2026-10-21T17:19:08+00:00","modified_at":"2026-10-22T14:17:47+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","fetched_at":"2026-10-23T22:29:01+00:00","note":null},{"source":"epss","external_id":"CVE-2026-76490","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-76490","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T13:15:54+00:00","fetched_at":"2026-10-24T13:15:54+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"}