Isc · Isc Dhcp · CVE-2022-2928
**Name of the Vulnerable Software and Affected Versions**
ISC DHCP versions 4.1-ESV-R1 through 4.1-ESV-R16-P1
ISC DHCP versions 4.4.0 through 4.4.3
**Description**
The issue is related to the function `add option()` in ISC DHCP, which is used in server responses to lease query packets. When `option code hash lookup()` is called from `add option()`, it increases the option's `refcount` field, but there is no corresponding call to `option dereference()` to decrement the `refcount` field. This can cause the reference counters to overflow, leading to a server abort. The vulnerability can be exploited by a remote attacker to cause a denial of service.
**Recommendations**
For ISC DHCP versions 4.1-ESV-R1 through 4.1-ESV-R16-P1, update to a version that includes a fix for the issue.
For ISC DHCP versions 4.4.0 through 4.4.3, update to a version that includes a fix for the issue.
As a temporary workaround, consider restricting access to the `add option()` function to minimize the risk of exploitation.