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CVE Record

CVE-2023-54265: ipv6: Fix an uninit variable access bug in __ip6_make_skb()

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2023-54265 is a Linux kernel IPv6 bug where raw IPv6 socket handling can read uninitialized data. The provided sources do not give a severity score or business impact. Treat it as a kernel hygiene issue that deserves normal patch management attention, especially on multi-user or container-host systems.

Executive priority

Use standard kernel patch cadence unless your environment has high local multi-tenant exposure. There is no source-backed evidence here of active exploitation or a remote unauthenticated attack path.

Technical view

The flaw is in __ip6_make_skb() during IPv6 raw socket send handling. The CVE states icmp6hdr may not be in the skb linear region for SOCK_RAW, and direct icmp6_hdr(skb)->icmp6_type access can trigger uninitialized-value use. The fix carries the ICMPv6 type in a local variable.

Likely exposure

Exposure applies to Linux systems running affected kernel versions listed in the CVE record, including ranges from 2.6.24 through 6.3 and several stable branches before fixes. Risk is most relevant where untrusted local users or workloads can use raw IPv6 sockets.

Exploitation context

The bundle shows syzbot/KMSAN discovery and kernel call traces through rawv6_sendmsg. It does not cite public exploitation, a weaponized proof of concept, or CISA KEV inclusion. Active exploitation should not be assumed from these sources.

Researcher notes

The available evidence is limited to the CVE text and stable kernel commit references. The vulnerability is an uninitialized-value access in IPv6 raw socket skb handling, with no CVSS, CWE, exploitability details, or distribution-specific advisories in the supplied bundle.

Mitigation direction

  • Apply Linux vendor kernel updates containing the referenced stable fixes.
  • Verify distribution backports if kernel version numbers do not visibly change.
  • Prioritize shared hosts, container platforms, and systems with untrusted local users.
  • If updates are unavailable, follow Linux distribution guidance for temporary controls.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and container hosts.
  • Compare versions against the CVE affected ranges and vendor advisories.
  • Check kernel changelogs for the fix title or referenced commit hashes.
  • Confirm patch status through distribution security trackers or package metadata.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2023-54265 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
9Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux14878f75abd5bf1d38becb405801cd491ee215dc, 14878f75abd5bf1d38becb405801cd491ee215dc, 14878f75abd5bf1d38becb405801cd491ee215dc, 14878f75abd5bf1d38becb405801cd491ee215dc, 14878f75abd5bf1d38becb405801cd491ee215dc, 14878f75abd5bf1d38becb405801cd491ee215dc, 14878f75abd5bf1d38becb405801cd491ee215dc, 14878f75abd5bf1d38becb405801cd491ee215dcunaffected
LinuxLinux2.6.24, 0, 4.14.313, 4.19.281, 5.4.241, 5.10.178, 5.15.107, 6.1.24, 6.2.11, 6.3affected
Weakness

CWE details

No CWE listed

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