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CVE-2024-56661

Status: ModifiedMedium (5.5)—

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

tipc: fix NULL deref in cleanup_bearer()

syzbot found [1] that after blamed commit, ub->ubsock->sk was NULL when attempting the atomic_dec() :

Fix this by caching the tipc_net pointer.

[1]

Technical details traces, logs and code from the original report
atomic_dec(&tipc_net(sock_net(ub->ubsock->sk))->wq_count);

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 UID: 0 PID: 5896 Comm: kworker/0:3 Not tainted 6.13.0-rc1-next-20241203-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events cleanup_bearer
 RIP: 0010:read_pnet include/net/net_namespace.h:387 [inline]
 RIP: 0010:sock_net include/net/sock.h:655 [inline]
 RIP: 0010:cleanup_bearer+0x1f7/0x280 net/tipc/udp_media.c:820
Code: 18 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 3c f7 99 f6 48 8b 1b 48 83 c3 30 e8 f0 e4 60 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 1a f7 99 f6 49 83 c7 e8 48 8b 1b
RSP: 0018:ffffc9000410fb70 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000030 RCX: ffff88802fe45a00
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc9000410f900
RBP: ffff88807e1f0908 R08: ffffc9000410f907 R09: 1ffff92000821f20
R10: dffffc0000000000 R11: fffff52000821f21 R12: ffff888031d19980
R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff88807e1f0918
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556ca050b000 CR3: 0000000031c0c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Linux — Linux Kernel

CWEs

References

Raw JSON (NVD)

Show
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  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix NULL deref in cleanup_bearer()\n\nsyzbot found [1] that after blamed commit, ub->ubsock->sk\nwas NULL when attempting the atomic_dec() :\n\natomic_dec(&tipc_net(sock_net(ub->ubsock->sk))->wq_count);\n\nFix this by caching the tipc_net pointer.\n\n[1]\n\nOops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN PTI\nKASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]\nCPU: 0 UID: 0 PID: 5896 Comm: kworker/0:3 Not tainted 6.13.0-rc1-next-20241203-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\nWorkqueue: events cleanup_bearer\n RIP: 0010:read_pnet include/net/net_namespace.h:387 [inline]\n RIP: 0010:sock_net include/net/sock.h:655 [inline]\n RIP: 0010:cleanup_bearer+0x1f7/0x280 net/tipc/udp_media.c:820\nCode: 18 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 3c f7 99 f6 48 8b 1b 48 83 c3 30 e8 f0 e4 60 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 1a f7 99 f6 49 83 c7 e8 48 8b 1b\nRSP: 0018:ffffc9000410fb70 EFLAGS: 00010206\nRAX: 0000000000000006 RBX: 0000000000000030 RCX: ffff88802fe45a00\nRDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc9000410f900\nRBP: ffff88807e1f0908 R08: ffffc9000410f907 R09: 1ffff92000821f20\nR10: dffffc0000000000 R11: fffff52000821f21 R12: ffff888031d19980\nR13: dffffc0000000000 R14: dffffc0000000000 R15: ffff88807e1f0918\nFS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000556ca050b000 CR3: 0000000031c0c000 CR4: 00000000003526f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: tipc: se corrige la deref NULL en cleanup_bearer() syzbot encontró [1] que después de el commit culpada, ub-&gt;ubsock-&gt;sk era NULL al intentar atomic_dec() : atomic_dec(&amp;tipc_net(sock_net(ub-&gt;ubsock-&gt;sk))-&gt;wq_count); Solucione esto almacenando en caché el puntero tipc_net. [1] Ups: error de protección general, probablemente para la dirección no canónica 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref en el rango [0x000000000000030-0x0000000000000037] CPU: 0 UID: 0 PID: 5896 Comm: kworker/0:3 No contaminado 6.13.0-rc1-next-20241203-syzkaller #0 Nombre del hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 13/09/2024 Cola de trabajo: eventos cleanup_bearer RIP: 0010:read_pnet include/net/net_namespace.h:387 [en línea] RIP: 0010:sock_net include/net/sock.h:655 [en línea] RIP: 0010:cleanup_bearer+0x1f7/0x280 net/tipc/udp_media.c:820 Código: 18 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 3c f7 99 f6 48 8b 1b 48 83 c3 30 e8 f0 e4 60 00 48 89 d8 48 c1 e8 03 &lt;42&gt; 80 3c 28 00 74 08 48 89 df e8 1a f7 99 f6 49 83 c7 e8 48 8b 1b RSP: 0018:ffffc9000410fb70 EFLAGS: 00010206 RAX: 0000000000000006 RBX: 0000000000000030 RCX: ffff88802fe45a00 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc9000410f900 RBP: ffff88807e1f0908 R08: ffffc9000410f907 R09: 1ffff92000821f20 R10: dffffc0000000000 R11: fffff52000821f21 R12: ffff888031d19980 R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff88807e1f0918 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000556ca050b000 CR3: 0000000031c0c000 CR4: 00000000003526f0 DR0: 00000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400"
    }
  ],
  "lastModified": "2026-06-17T08:12:40.850",
  "configurations": [
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}