Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

sctp: prevent peer transport count overflow

sctp_assoc_add_peer() increments the association's 16-bit transport_count for every new unique peer. Adding the 65,536th transport wraps the count to zero.

SCTP sock_diag uses transport_count to reserve the INET_DIAG_PEERS payload, then copies one sockaddr_storage for every entry in transport_addr_list. After the wrap, a diagnostic dump reserves an empty payload and writes 8 MiB of peer addresses past the skb tail.

Reject a new unique peer when transport_count has reached U16_MAX. Perform the check after the existing-peer lookup so a duplicate address continues to return its existing transport at the limit.