Advisory Published
Updated

CVE-2022-49904: net, neigh: Fix null-ptr-deref in neigh_table_clear()

First published: Thu May 01 2025(Updated: )

In the Linux kernel, the following vulnerability has been resolved: net, neigh: Fix null-ptr-deref in neigh_table_clear() When IPv6 module gets initialized but hits an error in the middle, kenel panic with: KASAN: null-ptr-deref in range [0x0000000000000598-0x000000000000059f] CPU: 1 PID: 361 Comm: insmod Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:__neigh_ifdown.isra.0+0x24b/0x370 RSP: 0018:ffff888012677908 EFLAGS: 00000202 ... Call Trace: <TASK> neigh_table_clear+0x94/0x2d0 ndisc_cleanup+0x27/0x40 [ipv6] inet6_init+0x21c/0x2cb [ipv6] do_one_initcall+0xd3/0x4d0 do_init_module+0x1ae/0x670 ... Kernel panic - not syncing: Fatal exception When ipv6 initialization fails, it will try to cleanup and calls: neigh_table_clear() neigh_ifdown(tbl, NULL) pneigh_queue_purge(&tbl->proxy_queue, dev_net(dev == NULL)) # dev_net(NULL) triggers null-ptr-deref. Fix it by passing NULL to pneigh_queue_purge() in neigh_ifdown() if dev is NULL, to make kernel not panic immediately.

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected SoftwareAffected VersionHow to fix
Linux Kernel

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Frequently Asked Questions

  • What is the severity of CVE-2022-49904?

    CVE-2022-49904 is classified as having a high severity due to the potential for kernel panic when the IPv6 module encounters an error.

  • How do I fix CVE-2022-49904?

    To mitigate CVE-2022-49904, update your Linux kernel to the latest stable version that includes the patch for this vulnerability.

  • What components are impacted by CVE-2022-49904?

    CVE-2022-49904 affects the IPv6 module within the Linux kernel, specifically during its initialization process.

  • What are the consequences of CVE-2022-49904?

    The primary consequence of CVE-2022-49904 is a kernel panic that can disrupt system reliability and availability.

  • What versions of Linux kernel are affected by CVE-2022-49904?

    CVE-2022-49904 impacts specific versions of the Linux kernel; users should review their current version and apply the necessary updates.

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