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

ipv6: Fix an uninit variable access bug in __ip6_make_skb()

Syzbot reported a bug as following:

=====================================================
BUG: KMSAN: uninit-value in arch_atomic64_inc arch/x86/include/asm/atomic64_64.h:88 [inline]
BUG: KMSAN: uninit-value in arch_atomic_long_inc include/linux/atomic/atomic-long.h:161 [inline]
BUG: KMSAN: uninit-value in atomic_long_inc include/linux/atomic/atomic-instrumented.h:1429 [inline]
BUG: KMSAN: uninit-value in __ip6_make_skb+0x2f37/0x30f0 net/ipv6/ip6_output.c:1956
arch_atomic64_inc arch/x86/include/asm/atomic64_64.h:88 [inline]
arch_atomic_long_inc include/linux/atomic/atomic-long.h:161 [inline]
atomic_long_inc include/linux/atomic/atomic-instrumented.h:1429 [inline]
__ip6_make_skb+0x2f37/0x30f0 net/ipv6/ip6_output.c:1956
ip6_finish_skb include/net/ipv6.h:1122 [inline]
ip6_push_pending_frames+0x10e/0x550 net/ipv6/ip6_output.c:1987
rawv6_push_pending_frames+0xb12/0xb90 net/ipv6/raw.c:579
rawv6_sendmsg+0x297e/0x2e60 net/ipv6/raw.c:922
inet_sendmsg+0x101/0x180 net/ipv4/af_inet.c:827
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
____sys_sendmsg+0xa8e/0xe70 net/socket.c:2476
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2530
__sys_sendmsg net/socket.c:2559 [inline]
__do_sys_sendmsg net/socket.c:2568 [inline]
__se_sys_sendmsg net/socket.c:2566 [inline]
__x64_sys_sendmsg+0x367/0x540 net/socket.c:2566
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was created at:
slab_post_alloc_hook mm/slab.h:766 [inline]
slab_alloc_node mm/slub.c:3452 [inline]
__kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
__do_kmalloc_node mm/slab_common.c:967 [inline]
__kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
kmalloc_reserve net/core/skbuff.c:492 [inline]
__alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
alloc_skb include/linux/skbuff.h:1270 [inline]
__ip6_append_data+0x51c1/0x6bb0 net/ipv6/ip6_output.c:1684
ip6_append_data+0x411/0x580 net/ipv6/ip6_output.c:1854
rawv6_sendmsg+0x2882/0x2e60 net/ipv6/raw.c:915
inet_sendmsg+0x101/0x180 net/ipv4/af_inet.c:827
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
____sys_sendmsg+0xa8e/0xe70 net/socket.c:2476
___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2530
__sys_sendmsg net/socket.c:2559 [inline]
__do_sys_sendmsg net/socket.c:2568 [inline]
__se_sys_sendmsg net/socket.c:2566 [inline]
__x64_sys_sendmsg+0x367/0x540 net/socket.c:2566
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

It is because icmp6hdr does not in skb linear region under the scenario
of SOCK_RAW socket. Access icmp6_hdr(skb)->icmp6_type directly will
trigger the uninit variable access bug.

Use a local variable icmp6_type to carry the correct value in different
scenarios.

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00035.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
14878f75abd5bf1d38becb405801cd491ee215dc affected < 165370522cc48127da564a08584a7391e6341908
14878f75abd5bf1d38becb405801cd491ee215dc affected < f394f690a30a5ec0413c62777a058eaf3d6e10d5
14878f75abd5bf1d38becb405801cd491ee215dc affected < 0cf600ca1bdf1d52df977516ee6cee0cadb1f6b1
14878f75abd5bf1d38becb405801cd491ee215dc affected < 605b056d63302ae84eb136e88d4df49124bd5e0d
14878f75abd5bf1d38becb405801cd491ee215dc affected < d65ff2fe877c471aa6e79efa7bd8ff66e147c317
14878f75abd5bf1d38becb405801cd491ee215dc affected < 2c9cefc142c1dc2759e19a92d3b2b3715e985beb
14878f75abd5bf1d38becb405801cd491ee215dc affected < 02ed5700f40445af02d1c97db25ffc2d04971d9f
14878f75abd5bf1d38becb405801cd491ee215dc affected < ea30388baebcce37fd594d425a65037ca35e59e8
Linux Linux affected
Version Status Constraints
2.6.24 affected —
0 unaffected < 2.6.24
4.14.313 unaffected ≤ 4.14.*
4.19.281 unaffected ≤ 4.19.*
5.4.241 unaffected ≤ 5.4.*
5.10.178 unaffected ≤ 5.10.*
5.15.107 unaffected ≤ 5.15.*
6.1.24 unaffected ≤ 6.1.*
6.2.11 unaffected ≤ 6.2.*
6.3 unaffected ≤ *

No data.

No data.

No data.

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/02ed5700f40445af02d1c97db25ffc2d04971d9f cve-icon cve-icon
https://git.kernel.org/stable/c/0cf600ca1bdf1d52df977516ee6cee0cadb1f6b1 cve-icon cve-icon
https://git.kernel.org/stable/c/165370522cc48127da564a08584a7391e6341908 cve-icon cve-icon
https://git.kernel.org/stable/c/2c9cefc142c1dc2759e19a92d3b2b3715e985beb cve-icon cve-icon
https://git.kernel.org/stable/c/605b056d63302ae84eb136e88d4df49124bd5e0d cve-icon cve-icon
https://git.kernel.org/stable/c/d65ff2fe877c471aa6e79efa7bd8ff66e147c317 cve-icon cve-icon
https://git.kernel.org/stable/c/ea30388baebcce37fd594d425a65037ca35e59e8 cve-icon cve-icon
https://git.kernel.org/stable/c/f394f690a30a5ec0413c62777a058eaf3d6e10d5 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025123059-CVE-2023-54265-02a6@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2023-54265 cve-icon
https://www.cve.org/CVERecord?id=CVE-2023-54265 cve-icon
History

Thu, 01 Jan 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Tue, 30 Dec 2025 12:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ipv6: Fix an uninit variable access bug in __ip6_make_skb() Syzbot reported a bug as following: ===================================================== BUG: KMSAN: uninit-value in arch_atomic64_inc arch/x86/include/asm/atomic64_64.h:88 [inline] BUG: KMSAN: uninit-value in arch_atomic_long_inc include/linux/atomic/atomic-long.h:161 [inline] BUG: KMSAN: uninit-value in atomic_long_inc include/linux/atomic/atomic-instrumented.h:1429 [inline] BUG: KMSAN: uninit-value in __ip6_make_skb+0x2f37/0x30f0 net/ipv6/ip6_output.c:1956 arch_atomic64_inc arch/x86/include/asm/atomic64_64.h:88 [inline] arch_atomic_long_inc include/linux/atomic/atomic-long.h:161 [inline] atomic_long_inc include/linux/atomic/atomic-instrumented.h:1429 [inline] __ip6_make_skb+0x2f37/0x30f0 net/ipv6/ip6_output.c:1956 ip6_finish_skb include/net/ipv6.h:1122 [inline] ip6_push_pending_frames+0x10e/0x550 net/ipv6/ip6_output.c:1987 rawv6_push_pending_frames+0xb12/0xb90 net/ipv6/raw.c:579 rawv6_sendmsg+0x297e/0x2e60 net/ipv6/raw.c:922 inet_sendmsg+0x101/0x180 net/ipv4/af_inet.c:827 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] ____sys_sendmsg+0xa8e/0xe70 net/socket.c:2476 ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2530 __sys_sendmsg net/socket.c:2559 [inline] __do_sys_sendmsg net/socket.c:2568 [inline] __se_sys_sendmsg net/socket.c:2566 [inline] __x64_sys_sendmsg+0x367/0x540 net/socket.c:2566 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was created at: slab_post_alloc_hook mm/slab.h:766 [inline] slab_alloc_node mm/slub.c:3452 [inline] __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491 __do_kmalloc_node mm/slab_common.c:967 [inline] __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988 kmalloc_reserve net/core/skbuff.c:492 [inline] __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565 alloc_skb include/linux/skbuff.h:1270 [inline] __ip6_append_data+0x51c1/0x6bb0 net/ipv6/ip6_output.c:1684 ip6_append_data+0x411/0x580 net/ipv6/ip6_output.c:1854 rawv6_sendmsg+0x2882/0x2e60 net/ipv6/raw.c:915 inet_sendmsg+0x101/0x180 net/ipv4/af_inet.c:827 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] ____sys_sendmsg+0xa8e/0xe70 net/socket.c:2476 ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2530 __sys_sendmsg net/socket.c:2559 [inline] __do_sys_sendmsg net/socket.c:2568 [inline] __se_sys_sendmsg net/socket.c:2566 [inline] __x64_sys_sendmsg+0x367/0x540 net/socket.c:2566 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd It is because icmp6hdr does not in skb linear region under the scenario of SOCK_RAW socket. Access icmp6_hdr(skb)->icmp6_type directly will trigger the uninit variable access bug. Use a local variable icmp6_type to carry the correct value in different scenarios.
Title ipv6: Fix an uninit variable access bug in __ip6_make_skb()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-12-30T12:15:57.557Z

Reserved: 2025-12-30T12:06:44.517Z

Link: CVE-2023-54265

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-12-30T13:16:15.300

Modified: 2025-12-31T20:42:43.210

Link: CVE-2023-54265

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-30T00:00:00Z

Links: CVE-2023-54265 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.