{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21678", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.738Z", "datePublished": "2025-01-31T11:25:39.500Z", "dateUpdated": "2026-08-05T11:53:34.427Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:53:34.427Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngtp: Destroy device along with udp socket's netns dismantle.\n\ngtp_newlink() links the device to a list in dev_net(dev) instead of\nsrc_net, where a udp tunnel socket is created.\n\nEven when src_net is removed, the device stays alive on dev_net(dev).\nThen, removing src_net triggers the splat below. [0]\n\nIn this example, gtp0 is created in ns2, and the udp socket is created\nin ns1.\n\n ip netns add ns1\n ip netns add ns2\n ip -n ns1 link add netns ns2 name gtp0 type gtp role sgsn\n ip netns del ns1\n\nLet's link the device to the socket's netns instead.\n\nNow, gtp_net_exit_batch_rtnl() needs another netdev iteration to remove\nall gtp devices in the netns.\n\n[0]:\nref_tracker: net notrefcnt@000000003d6e7d05 has 1/2 users at\n sk_alloc (./include/net/net_namespace.h:345 net/core/sock.c:2236)\n inet_create (net/ipv4/af_inet.c:326 net/ipv4/af_inet.c:252)\n __sock_create (net/socket.c:1558)\n udp_sock_create4 (net/ipv4/udp_tunnel_core.c:18)\n gtp_create_sock (./include/net/udp_tunnel.h:59 drivers/net/gtp.c:1423)\n gtp_create_sockets (drivers/net/gtp.c:1447)\n gtp_newlink (drivers/net/gtp.c:1507)\n rtnl_newlink (net/core/rtnetlink.c:3786 net/core/rtnetlink.c:3897 net/core/rtnetlink.c:4012)\n rtnetlink_rcv_msg (net/core/rtnetlink.c:6922)\n netlink_rcv_skb (net/netlink/af_netlink.c:2542)\n netlink_unicast (net/netlink/af_netlink.c:1321 net/netlink/af_netlink.c:1347)\n netlink_sendmsg (net/netlink/af_netlink.c:1891)\n ____sys_sendmsg (net/socket.c:711 net/socket.c:726 net/socket.c:2583)\n ___sys_sendmsg (net/socket.c:2639)\n __sys_sendmsg (net/socket.c:2669)\n do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)\n\nWARNING: CPU: 1 PID: 60 at lib/ref_tracker.c:179 ref_tracker_dir_exit (lib/ref_tracker.c:179)\nModules linked in:\nCPU: 1 UID: 0 PID: 60 Comm: kworker/u16:2 Not tainted 6.13.0-rc5-00147-g4c1224501e9d #5\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014\nWorkqueue: netns cleanup_net\nRIP: 0010:ref_tracker_dir_exit (lib/ref_tracker.c:179)\nCode: 00 00 00 fc ff df 4d 8b 26 49 bd 00 01 00 00 00 00 ad de 4c 39 f5 0f 85 df 00 00 00 48 8b 74 24 08 48 89 df e8 a5 cc 12 02 90 <0f> 0b 90 48 8d 6b 44 be 04 00 00 00 48 89 ef e8 80 de 67 ff 48 89\nRSP: 0018:ff11000009a07b60 EFLAGS: 00010286\nRAX: 0000000000002bd3 RBX: ff1100000f4e1aa0 RCX: 1ffffffff0e40ac6\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8423ee3c\nRBP: ff1100000f4e1af0 R08: 0000000000000001 R09: fffffbfff0e395ae\nR10: 0000000000000001 R11: 0000000000036001 R12: ff1100000f4e1af0\nR13: dead000000000100 R14: ff1100000f4e1af0 R15: dffffc0000000000\nFS: 0000000000000000(0000) GS:ff1100006ce80000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007f9b2464bd98 CR3: 0000000005286005 CR4: 0000000000771ef0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n \n ? __warn (kernel/panic.c:748)\n ? ref_tracker_dir_exit (lib/ref_tracker.c:179)\n ? report_bug (lib/bug.c:201 lib/bug.c:219)\n ? handle_bug (arch/x86/kernel/traps.c:285)\n ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))\n ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621)\n ? _raw_spin_unlock_irqrestore (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:97 ./arch/x86/include/asm/irqflags.h:155 ./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194)\n ? ref_tracker_dir_exit (lib/ref_tracker.c:179)\n ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:158)\n ? kfree (mm/slub.c:4613 mm/slub.c:4761)\n net_free (net/core/net_namespace.c:476 net/core/net_namespace.c:467)\n cleanup_net (net/core/net_namespace.c:664 (discriminator 3))\n process_one_work (kernel/workqueue.c:3229)\n worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391\n---truncated---" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is triggered entirely through local syscalls — an RTM_NEWLINK netlink message creating a GTP device with the link in a different netns than the netlink socket, followed by teardown of that netns. No remote packet processing is involved in reaching the bug.\nAC:L - The four-command reproducer in the commit message triggers it deterministically with no race and no dependence on uncontrolled memory layout; reoccupying the freed struct net is done by simply calling unshare(CLONE_NEWNET), which is fully under attacker control.\nPR:L - Both gates on the path (netlink_net_capable and rtnl_link_get_net_capable) check CAP_NET_ADMIN against net->user_ns, which an unprivileged user obtains for netns it creates via `unshare -Urn`; the gtp module is autoloaded on demand from the same path.\nUI:N - The attacker performs every step — creating the namespaces, creating the GTP link, and destroying the socket's namespace — with no action required from any other user.\nS:U - The dangling struct net pointer and the resulting corruption are confined to the kernel's own security authority; there is no hypervisor, IOMMU, or other authority boundary crossed.\nC:H - This is a use-after-free of struct net whose freed slab object the attacker can deterministically reoccupy, so subsequent reads through gtp->net and sock_net(sk) return attacker-groomed contents and route/socket lookups are performed against a foreign namespace's tables, enabling information disclosure.\nI:H - The teardown path performs __netns_tracker_free() on the freed net — a spinlock acquisition and list_del() into freed memory — giving a write-after-free/unlink primitive, and the aliased netns allows packets to be routed and sockets to be hashed into a namespace the attacker does not own.\nA:H - The bug reliably produces a ref_tracker_dir_exit() WARNING splat in cleanup_net (a panic under panic_on_warn), and the subsequent use-after-free of struct net causes kernel oopses/panics on device teardown or transmit." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/gtp.c" ], "versions": [ { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "c986380c1d5274c4d5e935addc807d6791cc23eb", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "5f1678346109ff3a6d229d33437fcba3cce9209d", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "036f8d814a2cd11ee8ef62b8f3e7ce5dec0ee4f3", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "efec287cbac92ac6ee8312a89221854760e13b34", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "bb11f992f5a475bc68ef959f17a55306f0328495", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "86f73d4ab2f27deeff22ba9336ad103d94f12ac7", "status": "affected", "versionType": "git" }, { "version": "459aa660eb1d8ce67080da1983bb81d716aa5a69", "lessThan": "eb28fd76c0a08a47b470677c6cef9dd1c60e92d1", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/gtp.c" ], "versions": [ { "version": "4.7", "status": "affected" }, { "version": "0", "lessThan": "4.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.290", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.234", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.177", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.127", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.74", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.11", "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": "4.7", "versionEndExcluding": "5.4.290" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "5.10.234" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "5.15.177" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.1.127" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.6.74" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.12.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c986380c1d5274c4d5e935addc807d6791cc23eb" }, { "url": "https://git.kernel.org/stable/c/5f1678346109ff3a6d229d33437fcba3cce9209d" }, { "url": "https://git.kernel.org/stable/c/036f8d814a2cd11ee8ef62b8f3e7ce5dec0ee4f3" }, { "url": "https://git.kernel.org/stable/c/efec287cbac92ac6ee8312a89221854760e13b34" }, { "url": "https://git.kernel.org/stable/c/bb11f992f5a475bc68ef959f17a55306f0328495" }, { "url": "https://git.kernel.org/stable/c/86f73d4ab2f27deeff22ba9336ad103d94f12ac7" }, { "url": "https://git.kernel.org/stable/c/eb28fd76c0a08a47b470677c6cef9dd1c60e92d1" } ], "title": "gtp: Destroy device along with udp socket's netns dismantle.", "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" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T20:58:55.888Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T12:03:10.577Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - BIOS", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html" }, { "url": "https://cert-portal.siemens.com/productcert/html/ssa-503939.html" } ] } ] } }