Vulnerability in Exim
CVE-2023-51766
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.
EPSS: 0.011 (61.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
Affected products
- Exim
- Debian Debian_linux — versions 10.0
- Fedoraproject Extra_packages_for_enterprise_linux — versions 7.0, 8.0, 9.0
- Fedoraproject Fedora — versions 38, 39
- N/a — versions n/a
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve@mitre.org (Technical Description, Third Party Advisory)
- cve@mitre.org (Broken Link)
- cve@mitre.org (Issue Tracking, Vendor Advisory)
- cve@mitre.org (Mailing List, Third Party Advisory, Issue Tracking)
- cve@mitre.org (mailing-list, Mailing List, Third Party Advisory)
- cve@mitre.org (mailing-list, Mailing List, Third Party Advisory)
- cve@mitre.org (Patch)
- cve@mitre.org (Patch)
- cve@mitre.org (Third Party Advisory, Issue Tracking)
- cve@mitre.org (Technical Description)
Frequently asked questions
- What is CVE-2023-51766?
- CVE-2023-51766 is a medium-severity vulnerability in Exim, classified under Insufficient Verification of Data Authenticity. CVSS score: 5.3/10. Published 2023-12-24.
- How severe is CVE-2023-51766?
- Medium severity. CVSS v3 base score is 5.3 out of 10.
- Is CVE-2023-51766 known to be exploited?
- 7 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.