CVE-2024-56751

MEDIUM EPSS 10.4%
Published Dec 29, 20241y ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Dec 29, 2024 1y ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: release nexthop on device removal The CI is hitting some aperiodic hangup at device removal time in the pmtu.sh self-test: unregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 6 ref_tracker: veth_A-R1@ffff888013df15d8 has 1/5 users at dst_init+0x84/0x4a0 dst_alloc+0x97/0x150 ip6_dst_alloc+0x23/0x90 ip6_rt_pcpu_alloc+0x1e6/0x520 ip6_pol_route+0x56f/0x840 fib6_rule_lookup+0x334/0x630 ip6_route_output_flags+0x259/0x480 ip6_dst_lookup_tail.constprop.0+0x5c2/0x940 ip6_dst_lookup_flow+0x88/0x190 udp_tunnel6_dst_lookup+0x2a7/0x4c0 vxlan_xmit_one+0xbde/0x4a50 [vxlan] vxlan_xmit+0x9ad/0xf20 [vxlan] dev_hard_start_xmit+0x10e/0x360 __dev_queue_xmit+0xf95/0x18c0 arp_solicit+0x4a2/0xe00 neigh_probe+0xaa/0xf0 While the first suspect is the dst_cache, explicitly tracking the dst owing the last device reference via probes proved such dst is held by the nexthop in the originating fib6_info. Similar to commit f5b51fe804ec ("ipv6: route: purge exception on removal"), we need to explicitly release the originating fib info when disconnecting a to-be-removed device from a live ipv6 dst: move the fib6_info cleanup into ip6_dst_ifdown(). Tested running: ./pmtu.sh cleanup_ipv6_exception in a tight loop for more than 400 iterations with no spat, running an unpatched kernel I observed a splat every ~10 iterations.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
10.4% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 4

VendorProductVersionRange
linuxlinux_kernel*≥5.3  –  <6.1.120
linuxlinux_kernel*≥6.2  –  <6.6.64
linuxlinux_kernel*≥6.7  –  <6.11.11
linuxlinux_kernel*≥6.12  –  <6.12.2

References 7

  • git.kernel.org https://git.kernel.org/stable/c/0e4c6faaef8a24b762a24ffb767280e263ef8e10
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/43e25adc80269f917d2a195f0d59f74cdd182955
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/77aa9855a878fb43f547ddfbda3127a1e88ad31a
  • git.kernel.org https://git.kernel.org/stable/c/a3c3f8a4d025acc8c857246ec2b812c59102487a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/b2f26a27ea3f72f75d18330f76f5d1007c791848
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/eb02688c5c45c3e7af7e71f036a7144f5639cbfe
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/0e4c6faaef8a24b762a24ffb767280e263ef8e10
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/43e25adc80269f917d2a195f0d59f74cdd182955
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a3c3f8a4d025acc8c857246ec2b812c59102487a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/b2f26a27ea3f72f75d18330f76f5d1007c791848
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/eb02688c5c45c3e7af7e71f036a7144f5639cbfe
    Patch