The index_urlfetch function in index.c in Cyrus IMAP 2.3.x before 2.3.19, 2.4.x before 2.4.18, 2.5.x before 2.5.4 allows remote attackers to obtain sensitive information or possibly have unspecified other impact via vectors related to the urlfetch range, which triggers an out-of-bounds heap read.

Integer overflow in the index_urlfetch function in imap/index.c in Cyrus IMAP 2.3.19, 2.4.18, and 2.5.6 allows remote attackers to have unspecified impact via vectors related to urlfetch range checks and the start_octet variable. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-8076.

Integer overflow in the index_urlfetch function in imap/index.c in Cyrus IMAP 2.3.19, 2.4.18, and 2.5.6 allows remote attackers to have unspecified impact via vectors related to urlfetch range checks and the section_offset variable. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-8076.

imap/nntpd.c in the NNTP server (nntpd) for Cyrus IMAPd 2.4.x before 2.4.12 allows remote attackers to bypass authentication by sending an AUTHINFO USER command without sending an additional AUTHINFO PASS command.

Stack-based buffer overflow in pop3d in Cyrus IMAPD (cyrus-imapd) 2.3.2, when the popsubfolders option is enabled, allows remote attackers to execute arbitrary code via a long USER command.

digestmd5.c in the CMU Cyrus Simple Authentication and Security Layer (SASL) library 2.1.18, and possibly other versions before 2.1.21, allows remote unauthenticated attackers to cause a denial of service (segmentation fault) via malformed inputs in DIGEST-MD5 negotiation.

Multiple buffer overflows in Cyrus IMAPd before 2.2.11 may allow attackers to execute arbitrary code via (1) an off-by-one error in the imapd annotate extension, (2) an off-by-one error in "cached header handling," (3) a stack-based buffer overflow in fetchnews, or (4) a stack-based buffer overflow in imapd.

The (1) libsasl and (2) libsasl2 libraries in Cyrus-SASL 2.1.18 and earlier trust the SASL_PATH environment variable to find all available SASL plug-ins, which allows local users to execute arbitrary code by modifying the SASL_PATH to point to malicious programs.

Buffer overflow in digestmd5.c CVS release 1.170 (also referred to as digestmda5.c), as used in the DIGEST-MD5 SASL plugin for Cyrus-SASL but not in any official releases, allows remote attackers to execute arbitrary code.

Multiple buffer overflows in Cyrus Sieve / libSieve 2.1.2 and earlier allow remote attackers to execute arbitrary code via (1) a long header name, (2) a long IMAP flag, or (3) a script that generates a large number of errors that overflow the resulting error string.