{"id":"CVE-2009-2055","published":"2009-08-19T17:30:01Z","modified":"2026-06-16T23:08:40Z","title":"Cisco IOS XR Border Gateway Protocol (BGP) Denial-of-Service Vulnerability","vendor":"Cisco","product":"IOS XR","tier":"core","eol":null,"description":{"text":"Cisco IOS XR 3.4.0 through 3.8.1 allows remote attackers to cause a denial of service (session reset) via a BGP UPDATE message with an invalid attribute, as demonstrated in the wild on 17 August 2009.","provenance":"source","from":"NVD"},"summary":{"text":"The flaw is an improper input validation weakness in the Border Gateway Protocol (BGP) component of Cisco IOS XR. An attacker with network access can send a BGP UPDATE message containing an invalid attribute to cause a denial of service through a session reset, with no authentication or user interaction required and no special configuration needed.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:14:27Z"},"cvss":{"score":5.9,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.03314,"percentile":0.88525,"date":"2026-10-28","provenance":"source"},"kev":{"dateAdded":"2022-03-25","dueDate":"2022-04-15","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2009-2055","provenance":"source"},"vulncheckKev":{"dateAdded":"2022-03-25","exploitedFirstSeen":"2022-03-25","ransomware":false,"evidence":[{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2022-03-25"}],"evidenceTotal":1,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-20","name":"Improper Input Validation"}],"references":[{"url":"http://mailman.nanog.org/pipermail/nanog/2009-August/012719.html","tags":["Mailing List"]},{"url":"http://securitytracker.com/id?1022739","tags":["Broken Link"]},{"url":"http://www.cisco.com/en/US/products/products_security_advisory09186a0080af150f.shtml","tags":["Patch","Vendor Advisory"]},{"url":"http://mailman.nanog.org/pipermail/nanog/2009-August/012719.html","tags":["Mailing List"]},{"url":"http://securitytracker.com/id?1022739","tags":["Broken Link"]},{"url":"http://www.cisco.com/en/US/products/products_security_advisory09186a0080af150f.shtml","tags":["Patch","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2009-2055","tags":["US Government Resource"]}],"techniques":[{"id":"T1499","name":"Endpoint Denial of Service","tactics":["impact"],"provenance":"source","basis":"ctid-cve","bases":["ctid-cve"],"basisDetail":"CTID attack_to_cve (Phase 1)","mappingType":"uncategorized","evidence":[],"confidence":"low","confidenceNote":"CTID attack_to_cve Phase 1 \"Uncategorized\" mapping (not staged by impact)"},{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Remote attacker sends crafted BGP message to router","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"allows remote attackers to cause a denial of service","start":33,"end":85}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1499.004","name":"Application or System Exploitation","tactics":["impact"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Session reset causes denial of service","mappingType":"primary_impact","evidence":[{"from":"description","quote":"cause a denial of service (session reset)","start":60,"end":101}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2009-2051","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2009-2051","exploited":true,"exploitedSince":"2022-03-25","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1499.004"],"provenance":"ai"},{"stage":"related","techniques":["T1499"],"provenance":"source","lowConfidence":true}],"timeline":[{"date":"2009-08-19","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2009-2055","provenance":"source"},{"date":"2022-03-25","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","provenance":"source"},{"date":"2022-03-25","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2022-03-25","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2009-2051","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":4601},"priority":{"score":59.8,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 1679 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":17.7,"detail":"percentile 0.8852"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":4.13,"detail":"base score 5.9"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]},"lineage":{"familyId":"fam-class-cisco-ios-xr-cwe-20"}}