{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-68241", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-16T13:41:40.263Z", "datePublished": "2025-12-16T14:21:18.682Z", "dateUpdated": "2026-08-05T12:10:24.792Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:10:24.792Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: route: Prevent rt_bind_exception() from rebinding stale fnhe\n\nThe sit driver's packet transmission path calls: sit_tunnel_xmit() ->\nupdate_or_create_fnhe(), which lead to fnhe_remove_oldest() being called\nto delete entries exceeding FNHE_RECLAIM_DEPTH+random.\n\nThe race window is between fnhe_remove_oldest() selecting fnheX for\ndeletion and the subsequent kfree_rcu(). During this time, the\nconcurrent path's __mkroute_output() -> find_exception() can fetch the\nsoon-to-be-deleted fnheX, and rt_bind_exception() then binds it with a\nnew dst using a dst_hold(). When the original fnheX is freed via RCU,\nthe dst reference remains permanently leaked.\n\nCPU 0 CPU 1\n__mkroute_output()\n find_exception() [fnheX]\n update_or_create_fnhe()\n fnhe_remove_oldest() [fnheX]\n rt_bind_exception() [bind dst]\n RCU callback [fnheX freed, dst leak]\n\nThis issue manifests as a device reference count leak and a warning in\ndmesg when unregistering the net device:\n\n unregister_netdevice: waiting for sitX to become free. Usage count = N\n\nIdo Schimmel provided the simple test validation method [1].\n\nThe fix clears 'oldest->fnhe_daddr' before calling fnhe_flush_routes().\nSince rt_bind_exception() checks this field, setting it to zero prevents\nthe stale fnhe from being reused and bound to a new dst just before it\nis freed.\n\n[1]\nip netns add ns1\nip -n ns1 link set dev lo up\nip -n ns1 address add 192.0.2.1/32 dev lo\nip -n ns1 link add name dummy1 up type dummy\nip -n ns1 route add 192.0.2.2/32 dev dummy1\nip -n ns1 link add name gretap1 up arp off type gretap \\\n local 192.0.2.1 remote 192.0.2.2\nip -n ns1 route add 198.51.0.0/16 dev gretap1\ntaskset -c 0 ip netns exec ns1 mausezahn gretap1 \\\n -A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &\ntaskset -c 2 ip netns exec ns1 mausezahn gretap1 \\\n -A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &\nsleep 10\nip netns pids ns1 | xargs kill\nip netns del ns1" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - On a router with a broad IPv4 route through a GRE/SIT tunnel, unauthenticated remote packets can reach both route-cache binding and tunnel PMTU exception eviction.\nAC:L - The attacker controls destination diversity and concurrency; parallel packet streams can fill exception buckets and repeatedly trigger both sides of the race despite randomized bucket limits.\nPR:N - The remote forwarding path has no authentication or capability check. Administrative privileges are needed to configure the router and tunnel, but not by an attacker sending packets through an existing deployment.\nUI:N - Exploitation requires only attacker-generated packet traffic and no action by a victim user.\nS:U - The leaked route and device references affect resources managed by the same kernel security authority and do not cross a virtualization or sandbox boundary.\nC:N - RCU keeps the stale exception allocated while it is used, so this is not a use-after-free, out-of-bounds access, or information-disclosure primitive.\nI:N - The bug loses a legitimate route reference without corrupting attacker-selected memory or enabling data modification or control-flow hijacking.\nA:H - Each successful race permanently leaks an rtable and net-device reference; repeated triggering can create unbounded memory pressure, while even one leak can make device or network-namespace teardown wait indefinitely." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/route.c" ], "versions": [ { "version": "e46e23c289f62ccd8e2230d9ce652072d777ff30", "lessThan": "69d35c12168f9c59b159ae566f77dfad9f96d7ca", "status": "affected", "versionType": "git" }, { "version": "5867e20e1808acd0c832ddea2587e5ee49813874", "lessThan": "4b7210da22429765d19460d38c30eeca72656282", "status": "affected", "versionType": "git" }, { "version": "67d6d681e15b578c1725bad8ad079e05d1c48a8e", "lessThan": "298f1e0694ab4edb6092d66efed93c4554e6ced1", "status": "affected", "versionType": "git" }, { "version": "67d6d681e15b578c1725bad8ad079e05d1c48a8e", "lessThan": "b8a44407bdaf2f0c5505cc7d9fc7d8da90cf9a94", "status": "affected", "versionType": "git" }, { "version": "67d6d681e15b578c1725bad8ad079e05d1c48a8e", "lessThan": "041ab9ca6e80d8f792bb69df28ebf1ef39c06af8", "status": "affected", "versionType": "git" }, { "version": "67d6d681e15b578c1725bad8ad079e05d1c48a8e", "lessThan": "b84f083f50ecc736a95091691339a1b363962f0e", "status": "affected", "versionType": "git" }, { "version": "67d6d681e15b578c1725bad8ad079e05d1c48a8e", "lessThan": "0fd16ed6dc331636fb2a874c42d2f7d3156f7ff0", "status": "affected", "versionType": "git" }, { "version": "67d6d681e15b578c1725bad8ad079e05d1c48a8e", "lessThan": "ac1499fcd40fe06479e9b933347b837ccabc2a40", "status": "affected", "versionType": "git" }, { "version": "bed8941fbdb72a61f6348c4deb0db69c4de87aca", "status": "affected", "versionType": "git" }, { "version": "f10ce783bcc4d8ea454563a7d56ae781640e7dcb", "status": "affected", "versionType": "git" }, { "version": "f484595be6b7ef9d095a32becabb5dae8204fb2a", "status": "affected", "versionType": "git" }, { "version": "3e6bd2b583f18da9856fc9741ffa200a74a52cba", "status": "affected", "versionType": "git" }, { "version": "5ae06218331f39ec45b5d039aa7cb3ddd4bb8008", "status": "affected", "versionType": "git" }, { "version": "4589a12dcf80af31137ef202be1ff4a321707a73", "status": "affected", "versionType": "git" }, { "version": "5.4.146", "lessThan": "5.4.302", "status": "affected", "versionType": "semver" }, { "version": "5.10.65", "lessThan": "5.10.247", "status": "affected", "versionType": "semver" }, { "version": "4.4.284", "lessThan": "4.5", "status": "affected", "versionType": "semver" }, { "version": "4.9.283", "lessThan": "4.10", "status": "affected", "versionType": "semver" }, { "version": "4.14.247", "lessThan": "4.15", "status": "affected", "versionType": "semver" }, { "version": "4.19.207", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.13.17", "lessThan": "5.14", "status": "affected", "versionType": "semver" }, { "version": "5.14.4", "lessThan": "5.15", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/route.c" ], "versions": [ { "version": "5.15", "status": "affected" }, { "version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.302", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.247", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.197", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.159", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.117", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.59", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.9", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "5.4.146", "versionEndExcluding": "5.4.302" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.65", "versionEndExcluding": "5.10.247" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "5.15.197" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.1.159" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.117" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.59" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.17.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4.284" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9.283" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.247" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.207" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13.17" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/69d35c12168f9c59b159ae566f77dfad9f96d7ca" }, { "url": "https://git.kernel.org/stable/c/4b7210da22429765d19460d38c30eeca72656282" }, { "url": "https://git.kernel.org/stable/c/298f1e0694ab4edb6092d66efed93c4554e6ced1" }, { "url": "https://git.kernel.org/stable/c/b8a44407bdaf2f0c5505cc7d9fc7d8da90cf9a94" }, { "url": "https://git.kernel.org/stable/c/041ab9ca6e80d8f792bb69df28ebf1ef39c06af8" }, { "url": "https://git.kernel.org/stable/c/b84f083f50ecc736a95091691339a1b363962f0e" }, { "url": "https://git.kernel.org/stable/c/0fd16ed6dc331636fb2a874c42d2f7d3156f7ff0" }, { "url": "https://git.kernel.org/stable/c/ac1499fcd40fe06479e9b933347b837ccabc2a40" } ], "title": "ipv4: route: Prevent rt_bind_exception() from rebinding stale fnhe", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-16T16:24:01.270292Z", "id": "CVE-2025-68241", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-16T16:24:13.146Z" } } ] } }