dhcpcd through 10.3.2, fixed in commit 78ea09e, contains a heap use-after-free vulnerability in the control socket handling within src/control.c that allows local unprivileged attackers to trigger memory corruption when privilege separation is disabled. Attackers can connect to the control socket and send a privileged command such as -x, causing controlrecvdata() to free the client object while the same READ+HANGUP event subsequently reaches controlhangup() with the stale pointer, resulting in a use-after-free condition exploitable in deployments using --disable-privsep or where privsep initialization has failed with the control socket operating in mode 0666.

dhcpcd Memory Leak DoS via IPv6 Router Advertisement Handling

dhcpcd through 10.3.2, fixed in commit 2f00c7b, contains a one-byte stack out-of-bounds write vulnerability in dhcp6makemessage() in src/dhcp6.c that allows unauthenticated same-link attackers to write beyond a fixed local buffer by serializing an oversized RFC6603 OPTIONPDEXCLUDE option body. Attackers can send a crafted DHCPv6 ADVERTISE message containing an IAPD IAPREFIX /0 with a valid OPTIONPDEXCLUDE using an exclude prefix length of /121 through /128 to trigger the out-of-bounds write and potentially corrupt adjacent stack memory.

dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unauthenticated same-link attackers to crash the daemon by sending a crafted DHCPv6 RENEW reply with RFC6603 OPTIONPDEXCLUDE and both preferred and valid lifetimes set to zero. Attackers acting as or impersonating a DHCPv6 server can trigger dhcp6deprecatedele() to free a delegated child address while an outer TAILQFOREACHSAFE iterator in dhcp6deprecateaddrs() still holds the freed pointer, causing a use-after-free when TAILQREMOVE is reached.

dhcp6.c in dhcpcd before 6.11.7 and 7.x before 7.2.2 has a buffer over-read in the D6OPTIONPDEXCLUDE feature.

dhcp.c in dhcpcd before 7.2.1 contains a 1-byte read overflow with DHOOPTSOVERLOADED.

auth.c in dhcpcd before 7.2.1 allowed attackers to infer secrets by performing latency attacks.

dhcpcd before 7.2.1 contains a buffer overflow in dhcp6findna in dhcp6.c when reading NA/TA addresses.

dhcpcd before 6.10.0 allows remote attackers to cause a denial of service (invalid read and crash) via vectors related to the option length.

dhcpcd before 6.10.0, as used in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-04-01 and other products, mismanages option lengths, which allows remote attackers to execute arbitrary code or cause a denial of service (heap-based buffer overflow) via a malformed DHCP response, aka internal bug 26461634.

The decodesearch function in dhcp.c in dhcpcd 3.x does not properly free allocated memory, which allows remote DHCP servers to cause a denial of service via a crafted response.

The decodesearch function in dhcp.c in dhcpcd 3.x allows remote DHCP servers to cause a denial of service (out-of-bounds write) via a crafted response.

The decodesearch function in dhcp.c in dhcpcd 3.x allows remote DHCP servers to cause a denial of service (out-of-bounds read) via a crafted response.

The printoption function in dhcp-common.c in dhcpcd through 6.9.1, as used in dhcp.c in dhcpcd 5.x in Android before 5.1 and other products, misinterprets the return value of the snprintf function, which allows remote DHCP servers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted message.

The getoption function in dhcp.c in dhcpcd before 6.2.0, as used in dhcpcd 5.x in Android before 5.1 and other products, does not validate the relationship between length fields and the amount of data, which allows remote DHCP servers to execute arbitrary code or cause a denial of service (memory corruption) via a large length value of an option in a DHCPACK message.

The getoption function in dhcpcd 4.0.0 through 6.x before 6.4.3 allows remote DHCP servers to cause a denial of service by resetting the DHOOPTIONSOVERLOADED option in the (1) bootfile or (2) servername section, which triggers the option to be processed again.