CVE-2026-74335

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

bpf: Fix NULL pointer dereference in bpftaskfrom_vpid()

bpftaskfromvpid() looks up a task in the pid namespace of the current task, via findtaskbyvpid():

findtaskbyvpid(vpid) findtaskbypidns(vpid, taskactivepidns(current)) findpidns(nr, ns) -> idr_find(&ns->idr, nr)

cgroupskb programs run in softirq, which may interrupt a task that is itself in doexit(). Once that task has passed exitnotify() -> releasetask() -> _unhashprocess(), its threadpid is cleared, so taskactivepidns(current) returns NULL and findpidns() dereferences &NULL->idr:

BUG: kernel NULL pointer dereference, address: 0000000000000050 RIP: 0010:idrfind+0x11/0x30 lib/idr.c:176 Call Trace: <IRQ> findpidns kernel/pid.c:370 [inline] findtaskbypidns+0x3b/0xe0 kernel/pid.c:485 bpftaskfromvpid+0x5b/0x200 kernel/bpf/helpers.c:2916 bpfprogrunarraycg+0x17e/0x530 kernel/bpf/cgroup.c:81 __cgroupbpfrunfilterskb+0x12b/0x250 kernel/bpf/cgroup.c:1612 skfiltertrimcap+0x1dc/0x4c0 net/core/filter.c:148 tcpv4rcv+0x18d1/0x2200 net/ipv4/tcpipv4.c:2223 </IRQ> <TASK> doexit+0xa63/0x1270 kernel/exit.c:1010 getsignal+0x141c/0x1530 kernel/signal.c:3037

Bail out when current has no pid namespace.