# CVE-2023-53831: net: read sk->sk_family once in sk_mc_loop() > A race condition in the Linux kernel's multicast loop handling can cause a kernel warning and potential denial of service. - **Severity:** Not scored - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 9 Dec 2025 - **Updated:** 11 May 2026 - **Also known as:** BELL-CVE-2023-53831, DEBIAN-CVE-2023-53831, GHSA-83cq-hc8w-3693, UBUNTU-CVE-2023-53831 ## What is CVE-2023-53831? CVE-2023-53831 is a vulnerability in Linux, published on 9 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim. ### Official 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 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 <0f> 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 ## Which versions are affected by CVE-2023-53831? ## How do I fix CVE-2023-53831? Apply the vendor's patch. ## Is CVE-2023-53831 being exploited? There is no known exploitation of CVE-2023-53831 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-53831 and fix it if it is affected. What it is: CVE-2023-53831 is a vulnerability in Linux, published on 9 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2023-53831 in the wild and no public exploit code. Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2023-53831/ (Markdown: https://insights.sbomify.com/CVE-2023-53831/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53831 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53831 - OSV: https://osv.dev/vulnerability/CVE-2023-53831 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-53831/ Summaries are generated and may contain mistakes; the official description above is the record.