status.cgi in Nagios 4.0 before 4.0 beta4 and 3.x before 3.5.1 does not properly restrict access to certain users that are a contact for a service, which allows remote authenticated users to obtain sensitive information about hostnames via the servicegroup (1) overview, (2) summary, or (3) grid style in status.cgi. NOTE: this behavior is by design in most 3.x versions, but the upstream vendor "decided to change it for Nagios 4" and 3.5.1.

Off-by-one error in the process_cgivars function in contrib/daemonchk.c in Nagios Core 3.5.1, 4.0.2, and earlier allows remote authenticated users to obtain sensitive information from process memory or cause a denial of service (crash) via a long string in the last key value in the variable list, which triggers a heap-based buffer over-read.

Multiple off-by-one errors in Nagios Core 3.5.1, 4.0.2, and earlier, and Icinga before 1.8.5, 1.9 before 1.9.4, and 1.10 before 1.10.2 allow remote authenticated users to obtain sensitive information from process memory or cause a denial of service (crash) via a long string in the last key value in the variable list to the process_cgivars function in (1) avail.c, (2) cmd.c, (3) config.c, (4) extinfo.c, (5) histogram.c, (6) notifications.c, (7) outages.c, (8) status.c, (9) statusmap.c, (10) summary.c, and (11) trends.c in cgi/, which triggers a heap-based buffer over-read.

Multiple stack-based buffer overflows in the get_history function in history.cgi in Nagios Core before 3.4.4, and Icinga 1.6.x before 1.6.2, 1.7.x before 1.7.4, and 1.8.x before 1.8.4, might allow remote attackers to execute arbitrary code via a long (1) host_name variable (host parameter) or (2) svc_description variable.