{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"state":"PUBLISHED","cveId":"CVE-2023-51766","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","assignerShortName":"mitre","dateUpdated":"2025-11-04T18:21:35.998Z","dateReserved":"2023-12-24T00:00:00.000Z","datePublished":"2023-12-24T00:00:00.000Z"},"containers":{"cna":{"providerMetadata":{"orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","shortName":"mitre","dateUpdated":"2024-01-18T02:47:22.078Z"},"descriptions":[{"lang":"en","value":"Exim before 4.97.1 allows SMTP smuggling in certain PIPELINING/CHUNKING configurations. Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because Exim supports <LF>.<CR><LF> but some other popular e-mail servers do not."}],"affected":[{"vendor":"n/a","product":"n/a","versions":[{"version":"n/a","status":"affected"}]}],"references":[{"url":"https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide/"},{"url":"https://exim.org/static/doc/security/CVE-2023-51766.txt"},{"url":"https://bugs.exim.org/show_bug.cgi?id=3063"},{"url":"https://www.openwall.com/lists/oss-security/2023/12/23/2"},{"name":"[oss-security] 20231224 Re: Re: New SMTP smuggling attack","tags":["mailing-list"],"url":"http://www.openwall.com/lists/oss-security/2023/12/24/1"},{"name":"[oss-security] 20231225 Re: Re: New SMTP smuggling 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