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CVE Record

CVE-2024-49952: netfilter: nf_tables: prevent nf_skb_duplicated corruption

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: prevent nf_skb_duplicated corruption syzbot found that nf_dup_ipv4() or nf_dup_ipv6() could write per-cpu variable nf_skb_duplicated in an unsafe way [1]. Disabling preemption as hinted by the splat is not enough, we have to disable soft interrupts as well. [1] BUG: using __this_cpu_write() in preemptible [00000000] code: syz.4.282/6316 caller is nf_dup_ipv4+0x651/0x8f0 net/ipv4/netfilter/nf_dup_ipv4.c:87 CPU: 0 UID: 0 PID: 6316 Comm: syz.4.282 Not tainted 6.11.0-rc7-syzkaller-00104-g7052622fccb1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 check_preemption_disabled+0x10e/0x120 lib/smp_processor_id.c:49 nf_dup_ipv4+0x651/0x8f0 net/ipv4/netfilter/nf_dup_ipv4.c:87 nft_dup_ipv4_eval+0x1db/0x300 net/ipv4/netfilter/nft_dup_ipv4.c:30 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288 nft_do_chain_ipv4+0x202/0x320 net/netfilter/nft_chain_filter.c:23 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook+0x2c4/0x450 include/linux/netfilter.h:269 NF_HOOK_COND include/linux/netfilter.h:302 [inline] ip_output+0x185/0x230 net/ipv4/ip_output.c:433 ip_local_out net/ipv4/ip_output.c:129 [inline] ip_send_skb+0x74/0x100 net/ipv4/ip_output.c:1495 udp_send_skb+0xacf/0x1650 net/ipv4/udp.c:981 udp_sendmsg+0x1c21/0x2a60 net/ipv4/udp.c:1269 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597 ___sys_sendmsg net/socket.c:2651 [inline] __sys_sendmmsg+0x3b2/0x740 net/socket.c:2737 __do_sys_sendmmsg net/socket.c:2766 [inline] __se_sys_sendmmsg net/socket.c:2763 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2763 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4ce4f7def9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4ce5d4a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f4ce5135f80 RCX: 00007f4ce4f7def9 RDX: 0000000000000001 RSI: 0000000020005d40 RDI: 0000000000000006 RBP: 00007f4ce4ff0b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f4ce5135f80 R15: 00007ffd4cbc6d68 </TASK>

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux kernel Netfilter flaw can corrupt per-CPU state when nftables duplicates IPv4 or IPv6 packets. Exploitation requires local access with low privileges according to the supplied CVSS assessment. Affected systems could face serious confidentiality, integrity, or availability impact, although the bundle does not document a demonstrated exploit.

Executive priority

Treat this as a high-priority kernel maintenance issue, especially on shared or locally accessible Linux hosts. It is less urgent than a confirmed remotely exploited flaw, but the supplied impact rating supports timely patching through normal emergency or accelerated maintenance procedures.

Technical view

The nf_dup_ipv4() and nf_dup_ipv6() paths could unsafely update the per-CPU nf_skb_duplicated variable. The kernel report shows __this_cpu_write() used in preemptible code through an nftables duplication expression. Disabling preemption alone is insufficient; the resolved implementation also disables soft interrupts around this state change.

Likely exposure

Exposure is limited to Linux systems running an affected kernel and exercising the relevant nftables packet-duplication paths. The supplied data identifies affected releases from 4.3 through several stable branches and 6.12, but distribution backports make version-only conclusions unreliable. Internet reachability alone does not establish exposure because the CVSS vector is local.

Exploitation context

The supplied CVSS 3.1 score is 7.8 with local, low-privilege access, low complexity, and no user interaction. The CVE is not listed as KEV, and the source bundle provides no evidence of active exploitation or a public weaponized exploit.

Researcher notes

The evidence is a syzbot-detected unsafe per-CPU write in IPv4 and IPv6 Netfilter duplication paths. The provided trace demonstrates a kernel correctness violation, not successful privilege escalation. Branch-specific stable commits are supplied, but no CWE, exploit proof, or detailed impact demonstration is included; validate remediation against the relevant vendor kernel package.

Mitigation direction

  • Upgrade to a distribution kernel containing the applicable upstream stable fix.
  • Use vendor advisories to map fixed packages because distributions may backport patches without changing upstream version identifiers.
  • Prioritize multi-user, container-hosting, and other systems where untrusted local users can interact with kernel networking features.

Validation and detection

  • Record each system's running kernel version and distribution package revision.
  • Check vendor changelogs for CVE-2024-49952 or the applicable referenced stable commit.
  • After maintenance, confirm the fixed kernel is running rather than merely installed.
  • Review whether nftables packet-duplication functionality is configured on potentially affected hosts.
Prepared
Confidence
high
Sources
12

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-2024-49952 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

1CVSS vectors
3Timeline events
3ADP providers
15Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2024-49952Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container
siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxd877f07112f1e5a247c6b585c971a93895c9f738, d877f07112f1e5a247c6b585c971a93895c9f738, d877f07112f1e5a247c6b585c971a93895c9f738, d877f07112f1e5a247c6b585c971a93895c9f738, d877f07112f1e5a247c6b585c971a93895c9f738, d877f07112f1e5a247c6b585c971a93895c9f738, d877f07112f1e5a247c6b585c971a93895c9f738, d877f07112f1e5a247c6b585c971a93895c9f738, d877f07112f1e5a247c6b585c971a93895c9f738unaffected
LinuxLinux4.3, 0, 4.19.323, 5.4.285, 5.10.227, 5.15.168, 6.1.113, 6.6.55, 6.10.14, 6.11.3, 6.12affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.