CVE-2023-53831

EPSS 0.0%
  • Published: 2025-12-09T16:17:22.017

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

net: read sk->sk_family once in sk_mc_loop()

syzbot is playing with IPV6_ADDRFORM quite a lot these days,
and managed to hit the WARN_ON_ONCE(1) in sk_mc_loop()

We have many more similar issues to fix.

WARNING: CPU: 1 PID: 1593 at net/core/sock.c:782 sk_mc_loop+0x165/0x260
Modules linked in:
CPU: 1 PID: 1593 Comm: kworker/1:3 Not tainted 6.1.40-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events_power_efficient gc_worker
RIP: 0010:sk_mc_loop+0x165/0x260 net/core/sock.c:782
Code: 34 1b fd 49 81 c7 18 05 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 ff e8 25 36 6d fd 4d 8b 37 eb 13 e8 db 33 1b fd 0b b3 01 eb 34 e8 d0 33 1b fd 45 31 f6 49 83 c6 38 4c 89 f0 48
RSP: 0018:ffffc90000388530 EFLAGS: 00010246
RAX: ffffffff846d9b55 RBX: 0000000000000011 RCX: ffff88814f884980
RDX: 0000000000000102 RSI: ffffffff87ae5160 RDI: 0000000000000011
RBP: ffffc90000388550 R08: 0000000000000003 R09: ffffffff846d9a65
R10: 0000000000000002 R11: ffff88814f884980 R12: dffffc0000000000
R13: ffff88810dbee000 R14: 0000000000000010 R15: ffff888150084000
FS: 0000000000000000(0000) GS:ffff8881f6b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 000000014ee5b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:

[] ip6_finish_output2+0x33f/0x1ae0 net/ipv6/ip6_output.c:83
[] __ip6_finish_output net/ipv6/ip6_output.c:200 [inline]
[] ip6_finish_output+0x6c6/0xb10 net/ipv6/ip6_output.c:211
[] NF_HOOK_COND include/linux/netfilter.h:298 [inline]
[] ip6_output+0x2bc/0x3d0 net/ipv6/ip6_output.c:232
[] dst_output include/net/dst.h:444 [inline]
[] ip6_local_out+0x10f/0x140 net/ipv6/output_core.c:161
[] ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:483 [inline]
[] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:529 [inline]
[] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
[] ipvlan_queue_xmit+0x1174/0x1be0 drivers/net/ipvlan/ipvlan_core.c:677
[] ipvlan_start_xmit+0x49/0x100 drivers/net/ipvlan/ipvlan_main.c:229
[] netdev_start_xmit include/linux/netdevice.h:4925 [inline]
[] xmit_one net/core/dev.c:3644 [inline]
[] dev_hard_start_xmit+0x320/0x980 net/core/dev.c:3660
[] sch_direct_xmit+0x2a0/0x9c0 net/sched/sch_generic.c:342
[] qdisc_restart net/sched/sch_generic.c:407 [inline]
[] __qdisc_run+0xb13/0x1e70 net/sched/sch_generic.c:415
[] qdisc_run+0xd6/0x260 include/net/pkt_sched.h:125
[] net_tx_action+0x7ac/0x940 net/core/dev.c:5247
[] __do_softirq+0x2bd/0x9bd kernel/softirq.c:599
[] invoke_softirq kernel/softirq.c:430 [inline]
[] __irq_exit_rcu+0xc8/0x170 kernel/softirq.c:683
[] irq_exit_rcu+0x9/0x20 kernel/softirq.c:695

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How to fix CVE-2023-53831

CVE-2023-53831 is a unknown severity vulnerability affecting the affected product.

Description: In the Linux kernel, the following vulnerability has been resolved: net: read sk->sk_family once in sk_mc_loop() syzbot is playing with IPV6_ADDRFORM quite a lot these days, and managed to hit the WARN_ON_ONCE(1) in sk_mc_loop() We have many more similar issues to fix. WARNING: CPU: 1 PID: 1593 at net/core/sock.c:782 sk_mc_loop+0x165/0x260 Modules linked in: CPU: 1 […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Dec 09, 2025
Vulnerability Published

CVE details first published to NVD database

Dec 09, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.