high 7.8

CVE-2026-43016 json

bpf: sockmap: Fix use-after-free of sk->sk_socket in sk_psock_verdict_data_ready().

published 2026-05-01 6 mo ago modified 2026-10-30 10 d ago also EUVD-2026-26615

cvss: 7.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits: 0; none known

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

syzbot reported use-after-free of AF_UNIX socket's sk->sk_socket in sk_psock_verdict_data_ready(). [0]

In unix_stream_sendmsg(), the peer socket's ->sk_data_ready() is called after dropping its unix_state_lock().

Although the sender socket holds the peer's refcount, it does not prevent the peer's sock_orphan(), and the peer's sk_socket might be freed after one RCU grace period.

Let's fetch the peer's sk->sk_socket and sk->sk_socket->ops under RCU in sk_psock_verdict_data_ready().

[0]: BUG: KASAN: slab-use-after-free in sk_psock_verdict_data_ready+0xec/0x590 net/core/skmsg.c:1278 Read of size 8 at addr ffff8880594da860 by task syz.4.1842/11013

CPU: 1 UID: 0 PID: 11013 Comm: syz.4.1842 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 sk_psock_verdict_data_ready+0xec/0x590 net/core/skmsg.c:1278 unix_stream_sendmsg+0x8a3/0xe80 net/unix/af_unix.c:2482 sock_sendmsg_nosec net/socket.c:721 [inline] __sock_sendmsg net/socket.c:736 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2585 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2639 __sys_sendmsg net/socket.c:2671 [inline] __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2674 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7facf899c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007facf9827028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007facf8c15fa0 RCX: 00007facf899c819 RDX: 0000000000000000 RSI: 0000200000000500 RDI: 0000000000000004 RBP: 00007facf8a32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007facf8c16038 R14: 00007facf8c15fa0 R15: 00007ffd41b01c78 </TASK>

Allocated by task 11013: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_lru_noprof+0x2b8/0x640 mm/slub.c:4885 sock_alloc_inode+0x28/0xc0 net/socket.c:316 alloc_inode+0x6a/0x1b0 fs/inode.c:347 new_inode_pseudo include/linux/fs.h:3003 [inline] sock_alloc net/socket.c:631 [inline] __sock_create+0x12d/0x9d0 net/socket.c:1562 sock_create net/socket.c:1656 [inline] __sys_socketpair+0x1c4/0x560 net/socket.c:1803 __do_sys_socketpair net/socket.c:1856 [inline] __se_sys_socketpair net/socket.c:1853 [inline] __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1853 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 15: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kmem_cache_free+0x187/0x630 mm/slub.c:6295 rcu_do_batch kernel/rcu/tree.c: ---truncated---

Patch / fix

fixed in 1 distros 4 links 6

Linux Linux 6.1.191, 6.6.134, 6.12.81, 6.18.22, 6.19.12, 7.0

debian ubuntu suse opensuse

linux Debian 13 6.12.85-1
linux Debian 14 6.19.12-1

debian advisories DEBIAN-CVE-2026-43016

linux Ubuntu 24.04 LTS 6.8.0-136.136
linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72
linux-gke Ubuntu 24.04 LTS 6.8.0-1059.67
linux-ibm Ubuntu 24.04 LTS 6.8.0-1061.62
linux-azure Ubuntu 24.04 LTS 6.8.0-1063.71
linux-gkeop Ubuntu 24.04 LTS 6.8.0-1046.50
linux-raspi Ubuntu 24.04 LTS 6.8.0-1061.65

ubuntu advisories UBUNTU-CVE-2026-43016

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

kernel-rt Real Time Module 15 SP7 6.4.0-150700.7.72.1
kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.72.1
kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.72.1
kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.78.1
kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.78.1
kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.78.1
kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.78.1
kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.78.1

suse advisories SUSE-SU-2026:3810-1 SUSE-SU-2026:3790-1 SUSE-SU-2026:23244-1 SUSE-SU-2026:23241-1 SUSE-SU-2026:23194-1 SUSE-SU-2026:23193-1

kernel-rt openSUSE Leap 16.0 6.12.0-160000.36.1
dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.36.1
kernel-64kb openSUSE Leap 16.0 6.12.0-160000.36.1
kernel-syms openSUSE Leap 16.0 6.12.0-160000.36.1
kernel-azure openSUSE Leap 16.0 6.12.0-160000.36.1
kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.36.1
kernel-source openSUSE Leap 16.0 6.12.0-160000.36.1
kernel-default openSUSE Leap 16.0 6.12.0-160000.36.1

opensuse advisories openSUSE-SU-2026:21388-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-43016 updated 2026-11-07 cvss 5.5

kernel: bpf: sockmap: Fix use-after-free of sk->sk_socket in sk_psock_verdict_data_ready()

Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
affected: no fix available “Fix deferred”
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 23 d ago (2026-10-16)

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Linux Linux

Classification

Weakness

CWE-416 Use After Free

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2026-43016
NVD CVE-2026-43016

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary