CVE-2026-53292
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk1th percentile — higher than 1% of all known CVEs
Summary
A vulnerability in the Linux kernel's Phonet subsystem causes a kernel BUG in pn_socket_autobind() when socket binding fails. The issue occurs when pn_socket_bind() returns -EINVAL due to invalid socket state with a zero port, leading to a kernel panic from a user-triggerable path.
Risk Assessment
An attacker can trigger a kernel panic by sending a crafted request to a Phonet socket, resulting in a denial of service (DoS) for the entire system.
Recommendation
Immediately update the Linux kernel to a version containing the fix that replaces BUG_ON() with returning -EINVAL. Check your distribution for the available patch and apply it.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: net: phonet: do not BUG_ON() in pn_socket_autobind() on failed bind syzbot reported a kernel BUG triggered from pn_socket_sendmsg() via pn_socket_autobind(): kernel BUG at net/phonet/socket.c:213! RIP: 0010:pn_socket_autobind net/phonet/socket.c:213 [inline] RIP: 0010:pn_socket_sendmsg+0x240/0x250 net/phonet/socket.c:421 Call Trace: sock_sendmsg_nosec+0x112/0x150 net/socket.c:797 __sock_sendmsg net/socket.c:812 [inline] __sys_sendto+0x402/0x590 net/socket.c:2280 ... pn_socket_autobind() calls pn_socket_bind() with port 0 and, on -EINVAL, assumes the socket was already bound and asserts that the port is non-zero: err = pn_socket_bind(sock, ..., sizeof(struct sockaddr_pn)); if (err != -EINVAL) return err; BUG_ON(!pn_port(pn_sk(sock->sk)->sobject)); return 0; /* socket was already bound */ However pn_socket_bind() also returns -EINVAL when sk->sk_state is not TCP_CLOSE, even when the socket has never been bound and pn_port() is still 0. In that case the BUG_ON() fires and panics the kernel from a user-triggerable path. Treat the "bind returned -EINVAL but pn_port() is still 0" case as a regular error and propagate -EINVAL to the caller instead of crashing. Existing callers already translate a non-zero return from pn_socket_autobind() into -ENOBUFS/-EAGAIN, so returning -EINVAL here only changes behaviour from panic to a normal errno.