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

udp: Set SOCK_RCU_FREE earlier in udp_lib_get_port().

syzkaller triggered the warning [0] in udp_v4_early_demux().

In udp_v[46]_early_demux() and sk_lookup(), we do not touch the refcount
of the looked-up sk and use sock_pfree() as skb->destructor, so we check
SOCK_RCU_FREE to ensure that the sk is safe to access during the RCU grace
period.

Currently, SOCK_RCU_FREE is flagged for a bound socket after being put
into the hash table. Moreover, the SOCK_RCU_FREE check is done too early
in udp_v[46]_early_demux() and sk_lookup(), so there could be a small race
window:

CPU1 CPU2
---- ----
udp_v4_early_demux() udp_lib_get_port()
| |- hlist_add_head_rcu()
|- sk = __udp4_lib_demux_lookup() |
|- DEBUG_NET_WARN_ON_ONCE(sk_is_refcounted(sk));
`- sock_set_flag(sk, SOCK_RCU_FREE)

We had the same bug in TCP and fixed it in commit 871019b22d1b ("net:
set SOCK_RCU_FREE before inserting socket into hashtable").

Let's apply the same fix for UDP.

[0]:
WARNING: CPU: 0 PID: 11198 at net/ipv4/udp.c:2599 udp_v4_early_demux+0x481/0xb70 net/ipv4/udp.c:2599
Modules linked in:
CPU: 0 PID: 11198 Comm: syz-executor.1 Not tainted 6.9.0-g93bda33046e7 #13
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:udp_v4_early_demux+0x481/0xb70 net/ipv4/udp.c:2599
Code: c5 7a 15 fe bb 01 00 00 00 44 89 e9 31 ff d3 e3 81 e3 bf ef ff ff 89 de e8 2c 74 15 fe 85 db 0f 85 02 06 00 00 e8 9f 7a 15 fe <0f> 0b e8 98 7a 15 fe 49 8d 7e 60 e8 4f 39 2f fe 49 c7 46 60 20 52
RSP: 0018:ffffc9000ce3fa58 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8318c92c
RDX: ffff888036ccde00 RSI: ffffffff8318c2f1 RDI: 0000000000000001
RBP: ffff88805a2dd6e0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0001ffffffffffff R12: ffff88805a2dd680
R13: 0000000000000007 R14: ffff88800923f900 R15: ffff88805456004e
FS: 00007fc449127640(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc449126e38 CR3: 000000003de4b002 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
PKRU: 55555554
Call Trace:
<TASK>
ip_rcv_finish_core.constprop.0+0xbdd/0xd20 net/ipv4/ip_input.c:349
ip_rcv_finish+0xda/0x150 net/ipv4/ip_input.c:447
NF_HOOK include/linux/netfilter.h:314 [inline]
NF_HOOK include/linux/netfilter.h:308 [inline]
ip_rcv+0x16c/0x180 net/ipv4/ip_input.c:569
__netif_receive_skb_one_core+0xb3/0xe0 net/core/dev.c:5624
__netif_receive_skb+0x21/0xd0 net/core/dev.c:5738
netif_receive_skb_internal net/core/dev.c:5824 [inline]
netif_receive_skb+0x271/0x300 net/core/dev.c:5884
tun_rx_batched drivers/net/tun.c:1549 [inline]
tun_get_user+0x24db/0x2c50 drivers/net/tun.c:2002
tun_chr_write_iter+0x107/0x1a0 drivers/net/tun.c:2048
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0x76f/0x8d0 fs/read_write.c:590
ksys_write+0xbf/0x190 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x41/0x50 fs/read_write.c:652
x64_sys_call+0xe66/0x1990 arch/x86/include/generated/asm/syscalls_64.h:2
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x4b/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7fc44a68bc1f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 e9 cf f5 ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 3c d0 f5 ff 48
RSP: 002b:00007fc449126c90 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004bc050 RCX: 00007fc44a68bc1f
R
---truncated---
Published: 2024-07-29
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4008-1 linux-6.1 security update
Debian DSA Debian DSA DSA-5747-1 linux security update
Ubuntu USN Ubuntu USN USN-7003-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7003-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7003-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7003-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7003-5 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7006-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7007-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7007-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7007-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7009-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7009-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7019-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-5 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-6 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7089-7 Linux kernel (Low Latency) vulnerabilities
Ubuntu USN Ubuntu USN USN-7090-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7095-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7156-1 Linux kernel (GKE) vulnerabilities
History

Mon, 03 Nov 2025 22:30:00 +0000

Type Values Removed Values Added
References

Thu, 09 Oct 2025 18:30:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.10:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.10:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.10:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.10:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.10:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.10:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.10:rc7:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Wed, 04 Dec 2024 14:45:00 +0000

Type Values Removed Values Added
CPEs cpe:/a:redhat:rhel_eus:9.2
cpe:/a:redhat:rhel_eus:9.2::nfv

Tue, 24 Sep 2024 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Redhat rhel Eus
CPEs cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:rhel_eus:8.8
Vendors & Products Redhat rhel Eus

Tue, 24 Sep 2024 06:30:00 +0000

Type Values Removed Values Added
CPEs cpe:/a:redhat:enterprise_linux:8::nfv

Wed, 11 Sep 2024 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 11 Sep 2024 13:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 06 Sep 2024 13:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-911
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

 cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Wed, 28 Aug 2024 22:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:9
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux

Subscriptions

Linux Linux Kernel
Redhat Enterprise Linux Rhel Eus
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T20:25:01.565Z

Reserved: 2024-07-12T12:17:45.623Z

Link: CVE-2024-41041

cve-icon Vulnrichment

Updated: 2024-08-02T04:39:56.185Z

cve-icon NVD

Status : Modified

Published: 2024-07-29T15:15:12.563

Modified: 2025-11-03T22:17:27.070

Link: CVE-2024-41041

cve-icon Redhat

Severity : Low

Publid Date: 2024-07-29T00:00:00Z

Links: CVE-2024-41041 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses