lldpd is an implementation of IEEE 802.1ab (LLDP). Prior to version 1.0.22, lldpd_decode() in src/daemon/lldpd.c strips 802.1Q VLAN tags from received Ethernet frames by calling memmove() to shift the frame payload 4 bytes left. The third argument (byte count) is s - 2 * ETHER_ADDR_LEN but should be s - 2 * ETHER_ADDR_LEN - 4, causing a 4-byte heap buffer over-read past the malloc(h_mtu) allocation when the received frame size equals the interface MTU. This issue has been patched in version 1.0.22.

An issue was discovered in lldpd before 1.0.17. By crafting a CDP PDU packet with specific CDP_TLV_ADDRESSES TLVs, a malicious actor can remotely force the lldpd daemon to perform an out-of-bounds read on heap memory. This occurs in cdp_decode in daemon/protocols/cdp.c.

In lldpd before 1.0.13, when decoding SONMP packets in the sonmp_decode function, it's possible to trigger an out-of-bounds heap read via short SONMP packets.