medium CVSS 5.5

CVE-2024-36008·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: ipv4: check for NULL idev in ip_route_use_hint() syzbot was able to trigger a NULL deref in fib_validate_source() in an old tree [1]. It appears the bug exists in latest trees. All calls to __in_dev_get_rcu() must be checked for a NULL result. [1] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 2 PID: 3257 Comm: syz-executor.3 Not tainted 5.10.0-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:fib_validate_source+0xbf/0x15a0 net/ipv4/fib_frontend.c:425 Code: 18 f2 f2 f2 f2 42 c7 44 20 23 f3 f3 f3 f3 48 89 44 24 78 42 c6 44 20 27 f3 e8 5d 88 48 fc 4c 89 e8 48 c1 e8 03 48 89 44 24 18 <42> 80 3c 20 00 74 08 4c 89 ef e8 d2 15 98 fc 48 89 5c 24 10 41 bf RSP: 0018:ffffc900015fee40 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88800f7a4000 RCX: ffff88800f4f90c0 RDX: 0000000000000000 RSI: 0000000004001eac RDI: ffff8880160c64c0 RBP: ffffc900015ff060 R08: 0000000000000000 R09: ffff88800f7a4000 R10: 0000000000000002 R11: ffff88800f4f90c0 R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88800f7a4000 FS: 00007f938acfe6c0(0000) GS:ffff888058c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f938acddd58 CR3: 000000001248e000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip_route_use_hint+0x410/0x9b0 net/ipv4/route.c:2231 ip_rcv_finish_core+0x2c4/0x1a30 net/ipv4/ip_input.c:327 ip_list_rcv_finish net/ipv4/ip_input.c:612 [inline] ip_sublist_rcv+0x3ed/0xe50 net/ipv4/ip_input.c:638 ip_list_rcv+0x422/0x470 net/ipv4/ip_input.c:673 __netif_receive_skb_list_ptype net/core/dev.c:5572 [inline] __netif_receive_skb_list_core+0x6b1/0x890 net/core/dev.c:5620 __netif_receive_skb_list net/core/dev.c:5672 [inline] netif_receive_skb_list_internal+0x9f9/0xdc0 net/core/dev.c:5764 netif_receive_skb_list+0x55/0x3e0 net/core/dev.c:5816 xdp_recv_frames net/bpf/test_run.c:257 [inline] xdp_test_run_batch net/bpf/test_run.c:335 [inline] bpf_test_run_xdp_live+0x1818/0x1d00 net/bpf/test_run.c:363 bpf_prog_test_run_xdp+0x81f/0x1170 net/bpf/test_run.c:1376 bpf_prog_test_run+0x349/0x3c0 kernel/bpf/syscall.c:3736 __sys_bpf+0x45c/0x710 kernel/bpf/syscall.c:5115 __do_sys_bpf kernel/bpf/syscall.c:5201 [inline] __se_sys_bpf kernel/bpf/syscall.c:5199 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5199

Severity
medium
Software
Kernel
Fixed in
6.8.9
Published
2024-05-20

Affected versions

From: 6.7

Until: 6.8.9

Fixed in: 6.8.9

How to fix this CVE

Update your Linux kernel to version 6.8.9 or later to patch a null pointer dereference vulnerability in IPv4 routing logic. This flaw can be triggered by local users during packet processing, leading to kernel crashes and denial of service. Apply the kernel update immediately through your distribution's package manager and reboot the system to activate the patched version.

sudo dnf update kernel && sudo reboot

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'uname -r' to display your current kernel version and verify if it falls within the vulnerable range (6.7 to 6.8.8)
  2. Check if IPv4 routing is active by examining 'cat /proc/net/route' to confirm the affected code path is in use
  3. Search kernel logs with 'sudo dmesg | grep -i "null pointer\|general protection fault\|fib_validate_source"' for signs of the vulnerability being triggered
  4. After patching, run 'uname -r' again and confirm the kernel version is 6.8.9 or later, then verify the system boots without crashes

FAQ

What is CVE-2024-36008?

This vulnerability is a null pointer dereference in the Linux kernel's IPv4 routing hint validation function, specifically in ip_route_use_hint(). When certain network conditions occur, the kernel fails to properly check if an interface device structure is valid before accessing it, causing a crash.

Is CVE-2024-36008 being actively exploited?

No, this vulnerability is not listed as actively exploited in the CISA KEV catalog, and no public exploits are currently available. However, it can be reliably triggered by local attackers with network access capabilities.

What versions of Kernel are affected by CVE-2024-36008?

Linux kernel versions 6.7 through 6.8.8 are vulnerable. Version 6.8.9 and later include the fix.

How do I check if my server is vulnerable to CVE-2024-36008?

Run 'uname -r' to see your kernel version. If it displays a version between 6.7 and 6.8.8 (inclusive), your system is vulnerable and requires an immediate update.

Does Defensia detect CVE-2024-36008?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2024-36008 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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CVE-2026-64439CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: crypto: krb5 - filter out async aead implementations at alloc krb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and rfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL completion callback and treat any negative return from crypto_aead_{encrypt,decrypt}() as terminal, falling through to kfree_sensitive(buffer). When the encrypt_name resolves to an async AEAD instance the request returns -EINPROGRESS, the buffer is freed while the backend's worker still holds a pointer, and the worker dereferences the freed slab on completion. KASAN report under UML+SLUB with a synthetic async aead backend bound to krb5->encrypt_name: BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7 The helpers were written synchronously, so filter the async instances out at allocation time instead of plumbing crypto_wait_req() through every call site. Reachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and net/ceph/crypto.c on systems with an async AEAD provider bound to the krb5 enctype name.
CVE-2026-64047CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: net: tls: fix off-by-one in sg_chain entry count for wrapped sk_msg ring When an sk_msg scatterlist ring wraps (sg.end < sg.start), tls_push_record() chains the tail portion of the ring to the head using sg_chain(). An extra entry in the sg array is reserved for this: struct sk_msg_sg { [...] /* The extra two elements: * 1) used for chaining the front and sections when the list becomes * partitioned (e.g. end < start). The crypto APIs require the * chaining; * 2) to chain tailer SG entries after the message. */ struct scatterlist data[MAX_MSG_FRAGS + 2]; The current code uses MAX_SKB_FRAGS + 1 as the ring size: sg_chain(&msg_pl->sg.data[msg_pl->sg.start], MAX_SKB_FRAGS - msg_pl->sg.start + 1, msg_pl->sg.data); This places the chain pointer at sg_chain(data[start], (MAX_SKB_FRAGS - msg_start + 1) .. = &data[start] + (MAX_SKB_FRAGS - msg_start + 1) - 1 = data[start + (MAX_SKB_FRAGS - start + 1) - 1] = data[MAX_SKB_FRAGS] instead of the true last entry. This is likely due to a "race" of the commit under Fixes landing close to commit 031097d9e079 ("bpf: sk_msg, zap ingress queue on psock down") Convert to ARRAY_SIZE and drop the data[start] / - start (as suggested by Sabrina).
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References

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