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CVE Record

CVE-2024-40961: ipv6: prevent possible NULL deref in fib6_nh_init()

In the Linux kernel, the following vulnerability has been resolved: ipv6: prevent possible NULL deref in fib6_nh_init() syzbot reminds us that in6_dev_get() can return NULL. fib6_nh_init() ip6_validate_gw( &idev ) ip6_route_check_nh( idev ) *idev = in6_dev_get(dev); // can be NULL Oops: general protection fault, probably for non-canonical address 0xdffffc00000000bc: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x00000000000005e0-0x00000000000005e7] CPU: 0 PID: 11237 Comm: syz-executor.3 Not tainted 6.10.0-rc2-syzkaller-00249-gbe27b8965297 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 RIP: 0010:fib6_nh_init+0x640/0x2160 net/ipv6/route.c:3606 Code: 00 00 fc ff df 4c 8b 64 24 58 48 8b 44 24 28 4c 8b 74 24 30 48 89 c1 48 89 44 24 28 48 8d 98 e0 05 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 b3 17 00 00 8b 1b 31 ff 89 de e8 b8 8b RSP: 0018:ffffc900032775a0 EFLAGS: 00010202 RAX: 00000000000000bc RBX: 00000000000005e0 RCX: 0000000000000000 RDX: 0000000000000010 RSI: ffffc90003277a54 RDI: ffff88802b3a08d8 RBP: ffffc900032778b0 R08: 00000000000002fc R09: 0000000000000000 R10: 00000000000002fc R11: 0000000000000000 R12: ffff88802b3a08b8 R13: 1ffff9200064eec8 R14: ffffc90003277a00 R15: dffffc0000000000 FS: 00007f940feb06c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000245e8000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ip6_route_info_create+0x99e/0x12b0 net/ipv6/route.c:3809 ip6_route_add+0x28/0x160 net/ipv6/route.c:3853 ipv6_route_ioctl+0x588/0x870 net/ipv6/route.c:4483 inet6_ioctl+0x21a/0x280 net/ipv6/af_inet6.c:579 sock_do_ioctl+0x158/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 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: 0033:0x7f940f07cea9

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2024-40961 is a Linux kernel IPv6 routing bug that can crash the kernel when a missing IPv6 device structure is dereferenced. The public record shows a resolved NULL pointer dereference, not data theft or remote code execution. Business impact is mainly availability risk on affected Linux systems and embedded products using vulnerable kernels.

Executive priority

Patch through normal kernel maintenance, faster for routers, appliances, hosts with IPv6 routing, and availability-critical systems. There is no sourced evidence of active exploitation, but kernel crashes can still create operational outages.

Technical view

The flaw is in fib6_nh_init() during IPv6 next-hop initialization. in6_dev_get() can return NULL through ip6_validate_gw()/ip6_route_check_nh(), but the path later dereferences it, causing a KASAN-reported NULL pointer dereference and general protection fault in the IPv6 route add ioctl path.

Likely exposure

Exposure is Linux systems running affected kernel versions or vendor products that include those kernels. The bundle lists Linux kernel stable fixes and downstream Debian and Siemens advisories. The sources do not define internet-facing reachability, required privileges, or a remote trigger condition.

Exploitation context

The CVE is not listed as KEV, and the provided sources do not claim active exploitation. Evidence comes from syzbot-style kernel crash reporting. Treat this as a denial-of-service risk until vendor guidance or environment-specific analysis shows broader impact.

Researcher notes

The record identifies a NULL dereference in IPv6 route initialization and includes the crashing stack trace. Public data in the bundle is insufficient to confirm exploitability beyond crash behavior, remote reachability, or privilege requirements. Avoid assuming code execution without additional vendor or kernel analysis.

Mitigation direction

  • Upgrade to a kernel package containing the referenced stable fixes.
  • Apply relevant Debian LTS or product vendor security updates.
  • Check Siemens advisories if using affected Siemens products.
  • Prioritize systems where IPv6 routing is enabled or operationally critical.
  • Follow vendor guidance if no patched package is available.

Validation and detection

  • Inventory Linux kernel versions and vendor appliance firmware versions.
  • Compare builds against distribution advisories and kernel stable fix references.
  • Confirm security scanners map CVE-2024-40961 to installed kernel packages.
  • Review kernel logs for fib6_nh_init, KASAN, or NULL dereference crashes.
  • Verify patched systems remain on supported vendor update channels.
Prepared
Confidence
medium
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-2024-40961 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
3ADP providers
12Source links

SSVC decision data

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

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

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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux428604fb118facce1309670779a35baf27ad044c, 428604fb118facce1309670779a35baf27ad044c, 428604fb118facce1309670779a35baf27ad044c, 428604fb118facce1309670779a35baf27ad044c, 428604fb118facce1309670779a35baf27ad044c, 428604fb118facce1309670779a35baf27ad044c, 428604fb118facce1309670779a35baf27ad044cunaffected
LinuxLinux4.17, 0, 5.4.279, 5.10.221, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10affected
Weakness

CWE details

No CWE listed

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