CVE-2021-47591

In the Linux kernel, the following vulnerability has been resolved: mptcp: remove tcp ulp setsockopt support TCP_ULP setsockopt cannot be used for mptcp because its already used internally to plumb subflow (tcp) sockets to the mptcp layer. syzbot managed to trigger a crash for mptcp connections that are in fallback mode: KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 1 PID: 1083 Comm: syz-executor.3 Not tainted 5.16.0-rc2-syzkaller #0 RIP: 0010:tls_build_proto net/tls/tls_main.c:776 [inline] [..] __tcp_set_ulp net/ipv4/tcp_ulp.c:139 [inline] tcp_set_ulp+0x428/0x4c0 net/ipv4/tcp_ulp.c:160 do_tcp_setsockopt+0x455/0x37c0 net/ipv4/tcp.c:3391 mptcp_setsockopt+0x1b47/0x2400 net/mptcp/sockopt.c:638 Remove support for TCP_ULP setsockopt.

Score

CVSS 3.1 5.5 Medium

Status

Modified - 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2024-06-19

Last modified

2026-05-11

Weaknesses

CWE-476

Affected products

• Linux Kernel (Linux)

References

• https://git.kernel.org/stable/c/3de0c86d42f841d1d64f316cd949e65c566f0734
• https://git.kernel.org/stable/c/404cd9a22150f24acf23a8df2ad0c094ba379f57