Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Exim | Exim | < 4.97.1 |
| Fedoraproject | Extra Packages For Enterprise Linux | 7.0 |
| Fedoraproject | Fedora | 38 |
| Debian | Debian Linux | 10.0 |
Related Weaknesses (CWE)
References
- http://www.openwall.com/lists/oss-security/2023/12/24/1Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2023/12/25/1Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2023/12/29/2Mailing ListMitigationThird Party Advisory
- http://www.openwall.com/lists/oss-security/2024/01/01/1Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2024/01/01/2Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2024/01/01/3Mailing ListThird Party Advisory
- https://bugs.exim.org/show_bug.cgi?id=3063Issue TrackingVendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2255852Issue TrackingThird Party Advisory
- https://exim.org/static/doc/security/CVE-2023-51766.txtBroken Link
- https://fahrplan.events.ccc.de/congress/2023/fahrplan/events/11782.htmlTechnical Description
- https://git.exim.org/exim.git/commit/5bb786d5ad568a88d50d15452aacc8404047e5caPatch
- https://git.exim.org/exim.git/commit/cf1376206284f2a4f11e32d931d4aade34c206c5Patch
- https://github.com/Exim/exim/blob/master/doc/doc-txt/cve-2023-51766MitigationVendor Advisory
- https://lists.debian.org/debian-lts-announce/2024/01/msg00002.htmlMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproMailing ListThird Party Advisory
FAQ
What is CVE-2023-51766?
CVE-2023-51766 is a vulnerability with a CVSS score of 5.3 (MEDIUM). 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 a...
How severe is CVE-2023-51766?
CVE-2023-51766 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2023-51766?
Check the references section above for vendor advisories and patch information. Affected products include: Exim Exim, Fedoraproject Extra Packages For Enterprise Linux, Fedoraproject Fedora, Debian Debian Linux.