{"id":"CVE-2010-4344","published":"2010-12-14T16:00:04Z","modified":"2026-06-16T23:24:36Z","title":"Exim Heap-Based Buffer Overflow Vulnerability","vendor":"Exim","product":"Exim","tier":"core","eol":null,"description":{"text":"Heap-based buffer overflow in the string_vformat function in string.c in Exim before 4.70 allows remote attackers to execute arbitrary code via an SMTP session that includes two MAIL commands in conjunction with a large message containing crafted headers, leading to improper rejection logging.","provenance":"source","from":"NVD"},"summary":{"text":"A heap-based buffer overflow in the string_vformat function in string.c of the Exim mail server, affecting versions before 4.70, is the flaw. An remote attacker can execute arbitrary code by sending an SMTP session containing two MAIL commands together with a large message with crafted headers, which triggers improper rejection logging, and no authentication or user interaction is required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:09:57Z"},"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":0.71706,"percentile":0.9942,"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-2010-4344","provenance":"source"},"vulncheckKev":{"dateAdded":"2010-12-10","exploitedFirstSeen":"2010-12-10","ransomware":false,"evidence":[{"url":"https://lists.exim.org/lurker/message/20101210.164935.385e04d0.en.html","date":"2010-12-10"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2022-03-25"}],"evidenceTotal":2,"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"},{"id":"CWE-119","name":"Improper Restriction of Operations within the Bounds of a Memory Buffer"}],"references":[{"url":"ftp://ftp.exim.org/pub/exim/ChangeLogs/ChangeLog-4.70","tags":["Broken Link"]},{"url":"http://atmail.com/blog/2010/atmail-6204-now-available/","tags":["Broken Link"]},{"url":"http://bugs.exim.org/show_bug.cgi?id=787","tags":["Issue Tracking","Patch"]},{"url":"http://git.exim.org/exim.git/commit/24c929a27415c7cfc7126c47e4cad39acf3efa6b","tags":["Mailing List","Patch"]},{"url":"http://lists.exim.org/lurker/message/20101210.164935.385e04d0.en.html","tags":["Mailing List","Patch"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2010-12/msg00003.html","tags":["Mailing List","Third Party Advisory"]},{"url":"http://openwall.com/lists/oss-security/2010/12/10/1","tags":["Mailing List","Third Party Advisory"]},{"url":"http://secunia.com/advisories/40019","tags":["Broken Link","Vendor Advisory"]},{"url":"http://secunia.com/advisories/42576","tags":["Broken 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Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3186","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3204","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3246","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3317","tags":["Broken Link"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=661756","tags":["Exploit","Issue Tracking"]},{"url":"ftp://ftp.exim.org/pub/exim/ChangeLogs/ChangeLog-4.70","tags":["Broken Link"]},{"url":"http://atmail.com/blog/2010/atmail-6204-now-available/","tags":["Broken Link"]},{"url":"http://bugs.exim.org/show_bug.cgi?id=787","tags":["Issue Tracking","Patch"]},{"url":"http://git.exim.org/exim.git/commit/24c929a27415c7cfc7126c47e4cad39acf3efa6b","tags":["Mailing List","Patch"]},{"url":"http://lists.exim.org/lurker/message/20101210.164935.385e04d0.en.html","tags":["Mailing List","Patch"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2010-12/msg00003.html","tags":["Mailing List","Third Party Advisory"]},{"url":"http://openwall.com/lists/oss-security/2010/12/10/1","tags":["Mailing List","Third Party Advisory"]},{"url":"http://secunia.com/advisories/40019","tags":["Broken Link","Vendor Advisory"]},{"url":"http://secunia.com/advisories/42576","tags":["Broken Link","Vendor Advisory"]},{"url":"http://secunia.com/advisories/42586","tags":["Broken Link","Vendor Advisory"]},{"url":"http://secunia.com/advisories/42587","tags":["Broken Link","Vendor Advisory"]},{"url":"http://secunia.com/advisories/42589","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.cpanel.net/2010/12/exim-remote-memory-corruption-vulnerability-notification-cve-2010-4344.html","tags":["Broken Link"]},{"url":"http://www.debian.org/security/2010/dsa-2131","tags":["Mailing List","Third Party 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Entry"]},{"url":"http://www.theregister.co.uk/2010/12/11/exim_code_execution_peril/","tags":["Press/Media Coverage"]},{"url":"http://www.ubuntu.com/usn/USN-1032-1","tags":["Third Party Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3171","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3172","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3181","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3186","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3204","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3246","tags":["Broken Link","Vendor Advisory"]},{"url":"http://www.vupen.com/english/advisories/2010/3317","tags":["Broken Link"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=661756","tags":["Exploit","Issue Tracking"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2010-4344","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 SMTP service exploited over network","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"allows remote attackers to execute arbitrary code via an SMTP session","start":90,"end":159}],"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: Code execution resulting from memory corruption","mappingType":"primary_impact","evidence":[{"from":"description","quote":"allows remote attackers to execute arbitrary code","start":90,"end":139}],"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-2010-4313","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2010-4313","exploited":true,"exploitedSince":"2022-03-25","provenance":"source"},"exploits":[{"id":15725,"url":"https://www.exploit-db.com/exploits/15725","title":"Exim 4.63 - Remote Command Execution","type":"remote","platform":"linux","date":"2010-12-11","verified":true,"provenance":"source"},{"id":16925,"url":"https://www.exploit-db.com/exploits/16925","title":"Exim4 < 4.69 - string_format Function Heap Buffer Overflow (Metasploit)","type":"remote","platform":"linux","date":"2010-12-16","verified":true,"provenance":"source"}],"exploitSources":{"exploitdb":{"count":2,"earliest":"2010-12-11"},"metasploit":[{"name":"Exim4 string_format Function Heap Buffer Overflow","module":"exploit/unix/smtp/exim4_string_format","type":"exploit","disclosureDate":"2010-12-07","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/smtp/exim4_string_format.rb"}],"first":{"date":"2010-12-07","source":"Metasploit","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/smtp/exim4_string_format.rb"},"provenance":"source"},"exploitRefs":["http://www.exim.org/lurker/message/20101207.215955.bb32d4f2.en.html","http://www.openwall.com/lists/oss-security/2021/05/04/7","http://www.osvdb.org/69685","https://bugzilla.redhat.com/show_bug.cgi?id=661756"],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"related","techniques":["T1203"],"provenance":"ai","lowConfidence":true}],"timeline":[{"date":"2010-12-07","kind":"exploit-public","label":"First public exploit: Metasploit; later: Exploit-DB 2010-12-11","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/smtp/exim4_string_format.rb","provenance":"source"},{"date":"2010-12-10","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://lists.exim.org/lurker/message/20101210.164935.385e04d0.en.html","provenance":"source"},{"date":"2010-12-14","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2010-4344","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-2010-4313","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":"Metasploit","daysToKev":4119},"priority":{"score":69.7,"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 5802 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.88,"detail":"percentile 0.9942"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"4 NVD references tagged Exploit; 2 Exploit-DB entries; 1 Metasploit module"},{"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"}]}}