{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2024-56751", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T11:26:39.759Z", "datePublished": "2024-12-29T11:30:16.805Z", "dateUpdated": "2026-05-11T20:58:23.094Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T20:58:23.094Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: release nexthop on device removal\n\nThe CI is hitting some aperiodic hangup at device removal time in the\npmtu.sh self-test:\n\nunregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 6\nref_tracker: veth_A-R1@ffff888013df15d8 has 1/5 users at\n\tdst_init+0x84/0x4a0\n\tdst_alloc+0x97/0x150\n\tip6_dst_alloc+0x23/0x90\n\tip6_rt_pcpu_alloc+0x1e6/0x520\n\tip6_pol_route+0x56f/0x840\n\tfib6_rule_lookup+0x334/0x630\n\tip6_route_output_flags+0x259/0x480\n\tip6_dst_lookup_tail.constprop.0+0x5c2/0x940\n\tip6_dst_lookup_flow+0x88/0x190\n\tudp_tunnel6_dst_lookup+0x2a7/0x4c0\n\tvxlan_xmit_one+0xbde/0x4a50 [vxlan]\n\tvxlan_xmit+0x9ad/0xf20 [vxlan]\n\tdev_hard_start_xmit+0x10e/0x360\n\t__dev_queue_xmit+0xf95/0x18c0\n\tarp_solicit+0x4a2/0xe00\n\tneigh_probe+0xaa/0xf0\n\nWhile the first suspect is the dst_cache, explicitly tracking the dst\nowing the last device reference via probes proved such dst is held by\nthe nexthop in the originating fib6_info.\n\nSimilar to commit f5b51fe804ec (\"ipv6: route: purge exception on\nremoval\"), we need to explicitly release the originating fib info when\ndisconnecting a to-be-removed device from a live ipv6 dst: move the\nfib6_info cleanup into ip6_dst_ifdown().\n\nTested running:\n\n./pmtu.sh cleanup_ipv6_exception\n\nin a tight loop for more than 400 iterations with no spat, running an\nunpatched kernel I observed a splat every ~10 iterations."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv6/route.c"], "versions": [{"version": "f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74", "lessThan": "77aa9855a878fb43f547ddfbda3127a1e88ad31a", "status": "affected", "versionType": "git"}, {"version": "f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74", "lessThan": "b2f26a27ea3f72f75d18330f76f5d1007c791848", "status": "affected", "versionType": "git"}, {"version": "f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74", "lessThan": "43e25adc80269f917d2a195f0d59f74cdd182955", "status": "affected", "versionType": "git"}, {"version": "f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74", "lessThan": "a3c3f8a4d025acc8c857246ec2b812c59102487a", "status": "affected", "versionType": "git"}, {"version": "f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74", "lessThan": "0e4c6faaef8a24b762a24ffb767280e263ef8e10", "status": "affected", "versionType": "git"}, {"version": "f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74", "lessThan": "eb02688c5c45c3e7af7e71f036a7144f5639cbfe", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv6/route.c"], "versions": [{"version": "5.3", "status": "affected"}, {"version": "0", "lessThan": "5.3", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.181", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.120", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.64", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.11.11", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.2", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.13", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "5.15.181"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.1.120"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.6.64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.11.11"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.12.2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.13"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/77aa9855a878fb43f547ddfbda3127a1e88ad31a"}, {"url": "https://git.kernel.org/stable/c/b2f26a27ea3f72f75d18330f76f5d1007c791848"}, {"url": "https://git.kernel.org/stable/c/43e25adc80269f917d2a195f0d59f74cdd182955"}, {"url": "https://git.kernel.org/stable/c/a3c3f8a4d025acc8c857246ec2b812c59102487a"}, {"url": "https://git.kernel.org/stable/c/0e4c6faaef8a24b762a24ffb767280e263ef8e10"}, {"url": "https://git.kernel.org/stable/c/eb02688c5c45c3e7af7e71f036a7144f5639cbfe"}], "title": "ipv6: release nexthop on device removal", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"title": "CVE Program Container", "references": [{"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T20:53:42.799Z"}}]}}

{}

{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "00376139-25FC-484F-BF0B-09AA1783B306", "versionEndExcluding": "6.1.120", "versionStartIncluding": "5.3", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "CA16DEE3-ABEC-4449-9F4A-7A3DC4FC36C7", "versionEndExcluding": "6.6.64", "versionStartIncluding": "6.2", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "21434379-192D-472F-9B54-D45E3650E893", "versionEndExcluding": "6.11.11", "versionStartIncluding": "6.7", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "D8882B1B-2ABC-4838-AC1D-DBDBB5764776", "versionEndExcluding": "6.12.2", "versionStartIncluding": "6.12", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: release nexthop on device removal\n\nThe CI is hitting some aperiodic hangup at device removal time in the\npmtu.sh self-test:\n\nunregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 6\nref_tracker: veth_A-R1@ffff888013df15d8 has 1/5 users at\n\tdst_init+0x84/0x4a0\n\tdst_alloc+0x97/0x150\n\tip6_dst_alloc+0x23/0x90\n\tip6_rt_pcpu_alloc+0x1e6/0x520\n\tip6_pol_route+0x56f/0x840\n\tfib6_rule_lookup+0x334/0x630\n\tip6_route_output_flags+0x259/0x480\n\tip6_dst_lookup_tail.constprop.0+0x5c2/0x940\n\tip6_dst_lookup_flow+0x88/0x190\n\tudp_tunnel6_dst_lookup+0x2a7/0x4c0\n\tvxlan_xmit_one+0xbde/0x4a50 [vxlan]\n\tvxlan_xmit+0x9ad/0xf20 [vxlan]\n\tdev_hard_start_xmit+0x10e/0x360\n\t__dev_queue_xmit+0xf95/0x18c0\n\tarp_solicit+0x4a2/0xe00\n\tneigh_probe+0xaa/0xf0\n\nWhile the first suspect is the dst_cache, explicitly tracking the dst\nowing the last device reference via probes proved such dst is held by\nthe nexthop in the originating fib6_info.\n\nSimilar to commit f5b51fe804ec (\"ipv6: route: purge exception on\nremoval\"), we need to explicitly release the originating fib info when\ndisconnecting a to-be-removed device from a live ipv6 dst: move the\nfib6_info cleanup into ip6_dst_ifdown().\n\nTested running:\n\n./pmtu.sh cleanup_ipv6_exception\n\nin a tight loop for more than 400 iterations with no spat, running an\nunpatched kernel I observed a splat every ~10 iterations."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ipv6: liberar el siguiente salto al eliminar el dispositivo. La CI est\u00e1 experimentando un bloqueo aperi\u00f3dico en el momento de eliminar el dispositivo en la prueba autom\u00e1tica pmtu.sh: unregister_netdevice: esperando a que veth_A-R1 se libere. Recuento de uso = 6 ref_tracker: veth_A-R1@ffff888013df15d8 tiene 1/5 usuarios en 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 Si bien el primer sospechoso es dst_cache, el seguimiento expl\u00edcito del dst que debe la \u00faltima referencia del dispositivo a trav\u00e9s de sondas demostr\u00f3 que dicho dst se mantiene en el siguiente salto en el fib6_info de origen. Similar a el commit f5b51fe804ec (\"ipv6: route: purge exception on removal\"), necesitamos liberar expl\u00edcitamente la informaci\u00f3n fib original al desconectar un dispositivo que se va a eliminar de un dst ipv6 activo: mueva la desinfecci\u00f3n fib6_info a ip6_dst_ifdown(). Probado ejecutando: ./pmtu.sh cleanup_ipv6_exception en un bucle cerrado durante m\u00e1s de 400 iteraciones sin splat, ejecutando un kernel sin parchear Observ\u00e9 un splat cada ~10 iteraciones."}], "id": "CVE-2024-56751", "lastModified": "2025-11-03T21:18:27.010", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2024-12-29T12:15:08.640", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/0e4c6faaef8a24b762a24ffb767280e263ef8e10"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/43e25adc80269f917d2a195f0d59f74cdd182955"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/77aa9855a878fb43f547ddfbda3127a1e88ad31a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/a3c3f8a4d025acc8c857246ec2b812c59102487a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b2f26a27ea3f72f75d18330f76f5d1007c791848"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/eb02688c5c45c3e7af7e71f036a7144f5639cbfe"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: ipv6: release nexthop on device removal", "id": "2334817", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2334817"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.4", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-404", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nipv6: release nexthop on device removal\nThe CI is hitting some aperiodic hangup at device removal time in the\npmtu.sh self-test:\nunregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 6\nref_tracker: veth_A-R1@ffff888013df15d8 has 1/5 users at\ndst_init+0x84/0x4a0\ndst_alloc+0x97/0x150\nip6_dst_alloc+0x23/0x90\nip6_rt_pcpu_alloc+0x1e6/0x520\nip6_pol_route+0x56f/0x840\nfib6_rule_lookup+0x334/0x630\nip6_route_output_flags+0x259/0x480\nip6_dst_lookup_tail.constprop.0+0x5c2/0x940\nip6_dst_lookup_flow+0x88/0x190\nudp_tunnel6_dst_lookup+0x2a7/0x4c0\nvxlan_xmit_one+0xbde/0x4a50 [vxlan]\nvxlan_xmit+0x9ad/0xf20 [vxlan]\ndev_hard_start_xmit+0x10e/0x360\n__dev_queue_xmit+0xf95/0x18c0\narp_solicit+0x4a2/0xe00\nneigh_probe+0xaa/0xf0\nWhile the first suspect is the dst_cache, explicitly tracking the dst\nowing the last device reference via probes proved such dst is held by\nthe nexthop in the originating fib6_info.\nSimilar to commit f5b51fe804ec (\"ipv6: route: purge exception on\nremoval\"), we need to explicitly release the originating fib info when\ndisconnecting a to-be-removed device from a live ipv6 dst: move the\nfib6_info cleanup into ip6_dst_ifdown().\nTested running:\n./pmtu.sh cleanup_ipv6_exception\nin a tight loop for more than 400 iterations with no spat, running an\nunpatched kernel I observed a splat every ~10 iterations.", "A flaw was found in the IPv6 implementation of the Linux kernel. When a network device is removed, the kernel fails to properly release associated nexthop references in certain cases. This can lead to stale references being held in the routing infrastructure, causing hangs or delays during device teardown. A local attacker could exploit this condition to cause denial of service during device removal, impacting system availability."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2024-56751", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2024-12-29T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2024-56751\nhttps://nvd.nist.gov/vuln/detail/CVE-2024-56751\nhttps://lore.kernel.org/linux-cve-announce/2024122927-CVE-2024-56751-bcf3@gregkh/T"], "statement": "For triggering requires privileges. The security impact is limited.", "threat_severity": "Moderate"}

{}