Zeek before 8.0.9 contains an uncontrolled memory consumption vulnerability in the FTP analyzer that allows unauthenticated remote attackers to cause process termination by sending a crafted FTP control session negotiating AUTH GSSAPI followed by a large ADAT control line. Attackers can exploit the NVT_Analyzer component's lack of a maximum line length check, causing it to continuously double its internal buffer without bounds during base64 decoding of an attacker-controlled ADAT token, resulting in denial of service of the Zeek sensor.

Zeek before 8.0.9 contains a null pointer dereference vulnerability in its Kerberos protocol analyzer that allows unauthenticated remote attackers to crash the sensor by sending a crafted KRB_ERROR message with error-code 25 (KDC_ERR_PREAUTH_REQUIRED) containing a PA-DATA element with padata-type 2, 3, 11, or 19. Attackers can exploit a parser and analyzer state mismatch where proc_padata() dereferences an uninitialized pa_data_element field selected by the wrong parsing arm, triggering a crash via a single UDP or TCP packet to port 88 without any credentials or prior authentication.