CVE-2021-25217

A flaw was found in the Dynamic Host Configuration Protocol (DHCP). There is a discrepancy between the code that handles encapsulated option information in leases transmitted "on the wire" and the code which reads and parses lease information after it has been written to disk storage. This flaw allows an attacker to deliberately cause a situation where dhcpd while running in DHCPv4 or DHCPv6 mode, or the dhclient attempts to read a stored lease that contains option information, to trigger a stack-based buffer overflow in the option parsing code for colon-separated hex digits values. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability.

To abuse this flaw an attacker has to be on the same local sub-net of the victim machine. An attacker may send crafted DHCP messages with long lease statements that, when stored locally on file and then re-read by dhclient or dhcpd, might trigger the bug.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.