CVE-2015-7687

Use-after-free vulnerability in OpenSMTPD before 5.7.2 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via vectors involving req_ca_vrfy_smtp and req_ca_vrfy_mta.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• http://lists.fedoraproject.org/pipermail/package-announce/2015-November/170448.html
• http://lists.fedoraproject.org/pipermail/package-announce/2015-October/169600.html
• http://www.openwall.com/lists/oss-security/2015/10/03/1
• http://www.securityfocus.com/bid/76975
• https://bugzilla.redhat.com/show_bug.cgi?id=1268793
• https://www.opensmtpd.org/announces/release-5.7.2.txt
• https://www.qualys.com/2015/10/02/opensmtpd-audit-report.txt
• http://lists.fedoraproject.org/pipermail/package-announce/2015-November/170448.html
• http://lists.fedoraproject.org/pipermail/package-announce/2015-October/169600.html
• http://www.openwall.com/lists/oss-security/2015/10/03/1
• http://www.securityfocus.com/bid/76975
• https://bugzilla.redhat.com/show_bug.cgi?id=1268793
• https://www.opensmtpd.org/announces/release-5.7.2.txt
• https://www.qualys.com/2015/10/02/opensmtpd-audit-report.txt