{"id":"DEBIAN-CVE-2026-74289","details":"In the Linux kernel, the following vulnerability has been resolved:  ipv4: fib: Don't dump dying fib_info in fib_leaf_notify().  syzbot reported use-after-free in nsim_fib4_prepare_event(). [0]  The problem is that the following functions call fib_info_hold() / refcount_inc() while dumping fib_info under RCU, which is unsafe.    * mlxsw_sp_router_fib4_event()   * rocker_router_fib_event()   * nsim_fib4_prepare_event()  refcount_inc_not_zero() must be used, but it would be too late there.  Let's guarantee the lifetime of fib_info in fib_leaf_notify().  Note that IPv6 does not need the corresponding change since fib6_table_dump() holds fib6_table.tb6_lock.  [0]: refcount_t: addition on 0; use-after-free. WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#0: kworker/u8:15/3420 Modules linked in: CPU: 0 UID: 0 PID: 3420 Comm: kworker/u8:15 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: netns cleanup_net RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25 Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 1b f1 22 fd 48 8d 3d 84 cb f1 0a 67 48 0f b9 3a eb 4a e8 08 f1 22 fd 48 8d 3d 81 cb f1 0a \u003c67\u003e 48 0f b9 3a eb 37 e8 f5 f0 22 fd 48 8d 3d 7e cb f1 0a 67 48 0f RSP: 0018:ffffc9000f2c7270 EFLAGS: 00010293 RAX: ffffffff84a18858 RBX: 0000000000000002 RCX: ffff888032ff9ec0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8f9353e0 RBP: 0000000000000000 R08: ffff888032ff9ec0 R09: 0000000000000005 R10: 0000000000000100 R11: 0000000000000004 R12: ffff8880570cc000 R13: dffffc0000000000 R14: ffff88802b40563c R15: ffff8880570cc000 FS:  0000000000000000(0000) GS:ffff888126173000(0000) knlGS:0000000000000000 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb1f4d5d000 CR3: 000000006072a000 CR4: 00000000003526f0 Call Trace:  \u003cTASK\u003e  __refcount_add include/linux/refcount.h:-1 [inline]  __refcount_inc include/linux/refcount.h:366 [inline]  refcount_inc include/linux/refcount.h:383 [inline]  fib_info_hold include/net/ip_fib.h:629 [inline]  nsim_fib4_prepare_event drivers/net/netdevsim/fib.c:930 [inline]  nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1000 [inline]  nsim_fib_event_nb+0x1055/0x1240 drivers/net/netdevsim/fib.c:1043  call_fib_notifier+0x45/0x80 net/core/fib_notifier.c:25  call_fib_entry_notifier net/ipv4/fib_trie.c:90 [inline]  fib_leaf_notify net/ipv4/fib_trie.c:2176 [inline]  fib_table_notify net/ipv4/fib_trie.c:2194 [inline]  fib_notify+0x36b/0x5e0 net/ipv4/fib_trie.c:2217  fib_net_dump net/core/fib_notifier.c:70 [inline]  register_fib_notifier+0x184/0x360 net/core/fib_notifier.c:108  nsim_fib_create+0x85d/0x9f0 drivers/net/netdevsim/fib.c:1596  nsim_dev_reload_create drivers/net/netdevsim/dev.c:1604 [inline]  nsim_dev_reload_up+0x374/0x7c0 drivers/net/netdevsim/dev.c:1058  devlink_reload+0x501/0x8d0 net/devlink/dev.c:475  devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:558  ops_pre_exit_list net/core/net_namespace.c:161 [inline]  ops_undo_list+0x187/0x940 net/core/net_namespace.c:234  cleanup_net+0x56e/0x800 net/core/net_namespace.c:702  process_one_work kernel/workqueue.c:3314 [inline]  process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397  worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478  kthread+0x388/0x470 kernel/kthread.c:436  ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245  \u003c/TASK\u003e","modified":"2026-10-04T13:00:15.414945828Z","published":"2026-08-15T06:22:28.457Z","upstream":["CVE-2026-74289"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-74289"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.129-1","6.1.133-1","6.1.135-1","6.1.137-1","6.1.139-1","6.1.140-1","6.1.147-1","6.1.148-1","6.1.153-1","6.1.158-1","6.1.159-1","6.1.162-1","6.1.164-1","6.1.170-1","6.1.170-2","6.1.170-3","6.1.172-1","6.1.174-1","6.1.176-1","6.1.177-1","6.1.180-1","6.1.187-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1","6.10-1~exp1","6.10.1-1~exp1","6.10.11-1","6.10.11-1~bpo12+1","6.10.12-1","6.10.3-1","6.10.4-1","6.10.6-1","6.10.6-1~bpo12+1","6.10.7-1","6.10.9-1","6.11-1~exp1","6.11.10-1","6.11.10-1~bpo12+1","6.11.2-1","6.11.4-1","6.11.5-1","6.11.5-1~bpo12+1","6.11.6-1","6.11.7-1","6.11.9-1","6.11~rc4-1~exp1","6.11~rc5-1~exp1","6.12.10-1","6.12.100-1","6.12.101-1","6.12.105-1","6.12.107-1","6.12.11-1","6.12.11-1+alpha","6.12.11-1+alpha.1","6.12.111-1","6.12.12-1","6.12.12-1~bpo12+1","6.12.13-1","6.12.15-1","6.12.16-1","6.12.17-1","6.12.19-1","6.12.20-1","6.12.21-1","6.12.22-1","6.12.22-1~bpo12+1","6.12.25-1","6.12.27-1","6.12.27-1~bpo12+1","6.12.29-1","6.12.3-1","6.12.30-1","6.12.30-1~bpo12+1","6.12.31-1","6.12.32-1","6.12.32-1~bpo12+1","6.12.33-1","6.12.33-1~bpo12+1","6.12.35-1","6.12.35-1~bpo12+1","6.12.37-1","6.12.38-1","6.12.38-1~bpo12+1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.5-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.6-1","6.12.63-1","6.12.63-1~bpo12+1","6.12.69-1","6.12.69-1~bpo12+1","6.12.73-1","6.12.73-1~bpo12+1","6.12.74-1","6.12.74-2","6.12.74-2~bpo12+1","6.12.8-1","6.12.85-1","6.12.85-1~bpo12+1","6.12.86-1","6.12.86-1~bpo12+1","6.12.88-1","6.12.88-1~bpo12+1","6.12.9-1","6.12.9-1+alpha","6.12.9-1~bpo12+1","6.12.90-1","6.12.90-1~bpo12+1","6.12.90-2","6.12.90-2~bpo12+1","6.12.94-1","6.12.94-1~bpo12+1","6.12.95-1","6.12.95-1~bpo12+1","6.12.96-1","6.12~rc6-1~exp1","6.13.10-1~exp1","6.13.11-1~exp1","6.13.2-1~exp1","6.13.3-1~exp1","6.13.4-1~exp1","6.13.5-1~exp1","6.13.6-1~exp1","6.13.7-1~exp1","6.13.8-1~exp1","6.13.9-1~exp1","6.13~rc6-1~exp1","6.13~rc7-1~exp1","6.14.3-1~exp1","6.14.5-1~exp1","6.14.6-1~exp1","6.15-1~exp1","6.15.1-1~exp1","6.15.2-1~exp1","6.15.3-1~exp1","6.15.4-1~exp1","6.15.5-1~exp1","6.15.6-1~exp1","6.15~rc7-1~exp1","6.16-1~exp1","6.16.1-1~exp1","6.16.10-1","6.16.11-1","6.16.12-1","6.16.12-1~bpo13+1","6.16.12-2","6.16.3-1","6.16.3-1~bpo13+1","6.16.5-1","6.16.6-1","6.16.7-1","6.16.8-1","6.16.9-1","6.16~rc7-1~exp1","6.17.10-1","6.17.11-1","6.17.12-1","6.17.13-1","6.17.13-1~bpo13+1","6.17.2-1~exp1","6.17.5-1~exp1","6.17.6-1","6.17.7-1","6.17.7-2","6.17.8-1","6.17.8-1~bpo13+1","6.17.9-1","6.18.1-1~exp1","6.18.10-1","6.18.12-1","6.18.12-1~bpo13+1","6.18.13-1","6.18.14-1","6.18.15-1","6.18.15-1~bpo13+1","6.18.2-1~exp1","6.18.3-1","6.18.5-1","6.18.5-1~bpo13+1","6.18.8-1","6.18.9-1","6.18.9-1~bpo13+1","6.18~rc4-1~exp1","6.18~rc4-1~exp2","6.18~rc5-1~exp1","6.18~rc6-1~exp1","6.18~rc7-1~exp1","6.19-1~exp1","6.19.10-1","6.19.10-1~bpo13+1","6.19.11-1","6.19.11-1~bpo13+1","6.19.12-1","6.19.13-1","6.19.13-1~bpo13+1","6.19.14-1","6.19.14-1~bpo13+1","6.19.2-1~exp1","6.19.3-1~exp1","6.19.4-1~exp1","6.19.5-1~exp1","6.19.6-1","6.19.6-2","6.19.6-2~bpo13+1","6.19.8-1","6.19.8-1~bpo13+1","6.19~rc4-1~exp1","6.19~rc5-1~exp1","6.19~rc6-1~exp1","6.19~rc7-1~exp1","6.19~rc8-1~exp1","6.3.1-1~exp1","6.3.11-1","6.3.2-1~exp1","6.3.4-1~exp1","6.3.5-1~exp1","6.3.7-1","6.3.7-1~bpo12+1","6.4.1-1~exp1","6.4.11-1","6.4.13-1","6.4.4-1","6.4.4-1~bpo12+1","6.4.4-2","6.4.4-3","6.4.4-3~bpo12+1","6.4~rc6-1~exp1","6.4~rc7-1~exp1","6.5.1-1~exp1","6.5.10-1","6.5.10-1~bpo12+1","6.5.13-1","6.5.3-1","6.5.3-1~bpo12+1","6.5.6-1","6.5.8-1","6.5~rc4-1~exp1","6.5~rc6-1~exp1","6.5~rc7-1~exp1","6.6.11-1","6.6.13-1","6.6.13-1~bpo12+1","6.6.15-1","6.6.15-2","6.6.3-1~exp1","6.6.4-1~exp1","6.6.7-1~exp1","6.6.8-1","6.6.9-1","6.7-1~exp1","6.7.1-1~exp1","6.7.12-1","6.7.12-1~bpo12+1","6.7.4-1~exp1","6.7.7-1","6.7.9-1","6.7.9-2","6.8.11-1","6.8.12-1","6.8.12-1~bpo12+1","6.8.9-1","6.9.10-1","6.9.10-1~bpo12+1","6.9.11-1","6.9.12-1","6.9.2-1~exp1","6.9.7-1","6.9.7-1~bpo12+1","6.9.8-1","6.9.9-1","7.0-1~exp1","7.0.1-1~exp1","7.0.10-1","7.0.10-1~bpo13+1","7.0.12-1","7.0.12-2","7.0.12-2~bpo13+1","7.0.13-1","7.0.13-1~bpo13+1","7.0.14-1","7.0.3-1","7.0.4-1","7.0.4-1~bpo13+1","7.0.7-1","7.0.7-1~bpo13+1","7.0.9-1","7.0.9-1~bpo13+1"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