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Vulnerability · Published Dec 29, 2024 · Assigned by Linux

CVE-2024-56751ipv6: release nexthop on device removal

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.2%top 87.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.123-1DEBIAN-CVE-2024-56751
Debian:13linux6.12.3-1DEBIAN-CVE-2024-56751
Debian:14linux6.12.3-1DEBIAN-CVE-2024-56751
Ubuntu:22.04:LTSlinux5.15.0-144.157UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux5.15.0-144.157USN-7654-1
Ubuntu:24.04:LTSlinux6.8.0-58.60UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-aws5.15.0-1088.95UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-aws5.15.0-1088.95USN-7654-1
Ubuntu:24.04:LTSlinux-aws6.8.0-1027.29UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1027.29~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-azure5.15.0-1094.103USN-7711-1
Ubuntu:22.04:LTSlinux-azure5.15.0-1094.103UBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-azure6.8.0-1027.32UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-azure-6.116.11.0-1012.12~24.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1027.32~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1094.103.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-azure-nvidia6.8.0-1014.15UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gcp5.15.0-1087.96UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gcp5.15.0-1087.96USN-7654-1
Ubuntu:24.04:LTSlinux-gcp6.8.0-1028.30UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-gcp-6.116.11.0-1011.11~24.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1028.30~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gke5.15.0-1085.91UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gke5.15.0-1085.91USN-7654-1
Ubuntu:24.04:LTSlinux-gke6.8.0-1023.27UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1070.78UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1070.78USN-7654-1
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1010.12UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-58.60~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-ibm5.15.0-1080.83USN-7654-1
Ubuntu:22.04:LTSlinux-ibm5.15.0-1080.83UBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-ibm6.8.0-1024.24UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1024.24~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1083.89UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1083.89USN-7654-1
Ubuntu:22.04:LTSlinux-kvm5.15.0-1084.89UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-kvm5.15.0-1084.89USN-7654-4
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-144.157UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-144.157USN-7654-1
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-58.60.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-58.60.1~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1082.83UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1082.83USN-7654-1
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1026.29UBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-nvidia-6.116.11.0-1007.7UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1026.29~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1026.29.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1041.41UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1041.41USN-7654-1
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1008.8UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1030.30UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1030.30USN-7654-1
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-oem-6.116.11.0-1015.15UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-oem-6.86.8.0-1026.26UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-oracle5.15.0-1085.91USN-7654-1
Ubuntu:22.04:LTSlinux-oracle5.15.0-1085.91UBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-oracle6.8.0-1024.25UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1024.25~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-raspi5.15.0-1083.86USN-7686-1
Ubuntu:22.04:LTSlinux-raspi5.15.0-1083.86UBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-raspi6.8.0-1028.32UBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-riscv6.8.0-58.60.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-58.60.1~22.04.1UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2024-56751
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1017.18UBUNTU-CVE-2024-56751
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1052.56USN-7654-5
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1052.56UBUNTU-CVE-2024-56751

Affected products (as reported)

VendorProductVersions
Linux Linux f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 – before 77aa9855a878fb43f547ddfbda3127a1e88ad31af88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 – before b2f26a27ea3f72f75d18330f76f5d1007c791848f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 – before 43e25adc80269f917d2a195f0d59f74cdd182955f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 – before a3c3f8a4d025acc8c857246ec2b812c59102487af88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 – before 0e4c6faaef8a24b762a24ffb767280e263ef8e10f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 – before eb02688c5c45c3e7af7e71f036a7144f5639cbfe
Linux Linux 5.3

References