{"id":"CVE-2019-16928","published":"2019-09-27T21:15:10Z","modified":"2026-06-17T02:22:58Z","title":"Exim Out-of-bounds Write Vulnerability","vendor":"Exim","product":"Exim Internet Mailer","tier":"core","eol":null,"description":{"text":"Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846. There is a heap-based buffer overflow in string_vformat in string.c involving a long EHLO command.","provenance":"source","from":"NVD"},"summary":{"text":"Exim Internet Mailer versions 4.92 through 4.92.2 contain a heap-based buffer overflow in the string_vformat function in string.c, triggered by an overlong EHLO command. A remote attacker with network access can exploit it without authentication or user interaction to achieve remote code execution.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:10:03Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.41638,"percentile":0.98678,"date":"2026-10-28","provenance":"source"},"kev":{"dateAdded":"2022-03-03","dueDate":"2022-03-17","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2019-16928","provenance":"source"},"vulncheckKev":{"dateAdded":"2022-03-03","exploitedFirstSeen":"2022-03-03","ransomware":false,"evidence":[{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2022-03-03"}],"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-787","name":"Out-of-bounds Write"}],"references":[{"url":"http://www.openwall.com/lists/oss-security/2019/09/28/1","tags":["Exploit","Mailing List","Mitigation","Third Party Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2019/09/28/2","tags":["Exploit","Mailing List","Third Party Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2019/09/28/3","tags":["Mailing List","Third Party Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2019/09/28/4","tags":["Mailing List","Third Party Advisory"]},{"url":"https://bugs.exim.org/show_bug.cgi?id=2449","tags":["Issue Tracking","Patch","Vendor Advisory"]},{"url":"https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d13670d65f","tags":["Patch"]},{"url":"https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.html","tags":["Vendor Advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EED7HM3MFIBAP5OIMJAFJ35JAJABTVSC/","tags":["Release Notes"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T3TJW4HPYH3O5HZCWGD6NSHTEBTTAPDC/","tags":["Release Notes"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UY6HPRW7MR3KBQ5JFHH6OXM7YCZBJCOB/","tags":["Release Notes"]},{"url":"https://seclists.org/bugtraq/2019/Sep/60","tags":["Mailing List","Third Party Advisory"]},{"url":"https://security.gentoo.org/glsa/202003-47","tags":["Third Party Advisory"]},{"url":"https://usn.ubuntu.com/4141-1/","tags":["Third Party Advisory"]},{"url":"https://www.debian.org/security/2019/dsa-4536","tags":["Third Party Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2019/09/28/1","tags":["Exploit","Mailing List","Mitigation","Third Party Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2019/09/28/2","tags":["Exploit","Mailing List","Third Party Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2019/09/28/3","tags":["Mailing List","Third Party Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2019/09/28/4","tags":["Mailing List","Third Party Advisory"]},{"url":"https://bugs.exim.org/show_bug.cgi?id=2449","tags":["Issue Tracking","Patch","Vendor Advisory"]},{"url":"https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d13670d65f","tags":["Patch"]},{"url":"https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.html","tags":["Vendor Advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EED7HM3MFIBAP5OIMJAFJ35JAJABTVSC/","tags":["Release Notes"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T3TJW4HPYH3O5HZCWGD6NSHTEBTTAPDC/","tags":["Release Notes"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UY6HPRW7MR3KBQ5JFHH6OXM7YCZBJCOB/","tags":["Release Notes"]},{"url":"https://seclists.org/bugtraq/2019/Sep/60","tags":["Mailing List","Third Party Advisory"]},{"url":"https://security.gentoo.org/glsa/202003-47","tags":["Third Party Advisory"]},{"url":"https://usn.ubuntu.com/4141-1/","tags":["Third Party Advisory"]},{"url":"https://www.debian.org/security/2019/dsa-4536","tags":["Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-16928","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Remote unauthenticated attack against public-facing mail service","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"allows remote code execution, a different vulnerability than CVE-2019-15846","start":25,"end":100}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1203","name":"Exploitation for Client Execution","tactics":["execution"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Overflow in parsing enables code execution","mappingType":"primary_impact","evidence":[{"from":"description","quote":"There is a heap-based buffer overflow in string_vformat in string.c","start":102,"end":169}],"model":"claude-haiku-5-5","confidence":"low","confidenceNote":"server-side bug exploitable without user interaction; client-execution technique does not fit"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2019-7422","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2019-7422","exploited":true,"exploitedSince":"2022-03-03","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":["http://www.openwall.com/lists/oss-security/2019/09/28/1","http://www.openwall.com/lists/oss-security/2019/09/28/2"],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"related","techniques":["T1203"],"provenance":"ai","lowConfidence":true}],"timeline":[{"date":"2019-09-27","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2019-16928","provenance":"source"},{"date":"2022-03-03","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":"2022-03-03","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2022-03-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2019-7422","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":888},"priority":{"score":69.6,"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 1701 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.74,"detail":"percentile 0.9868"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"2 NVD references tagged Exploit"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":6.86,"detail":"base score 9.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}