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CVE-2025-21858 (GCVE-0-2025-21858)

Vulnerability from cvelistv5 – Published: 2025-03-12 09:42 – Updated: 2026-08-05 11:54
VLAI
Title
geneve: Fix use-after-free in geneve_find_dev().
Summary
In the Linux kernel, the following vulnerability has been resolved: geneve: Fix use-after-free in geneve_find_dev(). syzkaller reported a use-after-free in geneve_find_dev() [0] without repro. geneve_configure() links struct geneve_dev.next to net_generic(net, geneve_net_id)->geneve_list. The net here could differ from dev_net(dev) if IFLA_NET_NS_PID, IFLA_NET_NS_FD, or IFLA_TARGET_NETNSID is set. When dev_net(dev) is dismantled, geneve_exit_batch_rtnl() finally calls unregister_netdevice_queue() for each dev in the netns, and later the dev is freed. However, its geneve_dev.next is still linked to the backend UDP socket netns. Then, use-after-free will occur when another geneve dev is created in the netns. Let's call geneve_dellink() instead in geneve_destroy_tunnels(). [0]: BUG: KASAN: slab-use-after-free in geneve_find_dev drivers/net/geneve.c:1295 [inline] BUG: KASAN: slab-use-after-free in geneve_configure+0x234/0x858 drivers/net/geneve.c:1343 Read of size 2 at addr ffff000054d6ee24 by task syz.1.4029/13441 CPU: 1 UID: 0 PID: 13441 Comm: syz.1.4029 Not tainted 6.13.0-g0ad9617c78ac #24 dc35ca22c79fb82e8e7bc5c9c9adafea898b1e3d Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x16c/0x6f0 mm/kasan/report.c:489 kasan_report+0xc0/0x120 mm/kasan/report.c:602 __asan_report_load2_noabort+0x20/0x30 mm/kasan/report_generic.c:379 geneve_find_dev drivers/net/geneve.c:1295 [inline] geneve_configure+0x234/0x858 drivers/net/geneve.c:1343 geneve_newlink+0xb8/0x128 drivers/net/geneve.c:1634 rtnl_newlink_create+0x23c/0x868 net/core/rtnetlink.c:3795 __rtnl_newlink net/core/rtnetlink.c:3906 [inline] rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:713 [inline] __sock_sendmsg net/socket.c:728 [inline] ____sys_sendmsg+0x410/0x6f8 net/socket.c:2568 ___sys_sendmsg+0x178/0x1d8 net/socket.c:2622 __sys_sendmsg net/socket.c:2654 [inline] __do_sys_sendmsg net/socket.c:2659 [inline] __se_sys_sendmsg net/socket.c:2657 [inline] __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2657 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151 el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600 Allocated by task 13247: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x68 mm/kasan/common.c:68 kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4298 [inline] __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4304 __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:645 alloc_netdev_mqs+0xb8/0x11a0 net/core/dev.c:11470 rtnl_create_link+0x2b8/0xb50 net/core/rtnetlink.c:3604 rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3780 __rtnl_newlink net/core/rtnetlink.c:3906 [inline] rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938 netlink_unicast_kernel net/netlink/af_n ---truncated---
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-03-12 13:19 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 2d07dc79fe04a43d82a346ced6bbf07bdb523f1b , < d5e86e27de0936f3cb0a299ce519d993e9cf3886 (git)
Affected: 2d07dc79fe04a43d82a346ced6bbf07bdb523f1b , < 5a0538ac6826807d6919f6aecbb8996c2865af2c (git)
Affected: 2d07dc79fe04a43d82a346ced6bbf07bdb523f1b , < f74f6560146714241c6e167b03165ee77a86e316 (git)
Affected: 2d07dc79fe04a43d82a346ced6bbf07bdb523f1b , < 904e746b2e7fa952ab8801b303ce826a63153d78 (git)
Affected: 2d07dc79fe04a43d82a346ced6bbf07bdb523f1b , < 3ce92ca990cfac88a87c61df3cc0b5880e688ecf (git)
Affected: 2d07dc79fe04a43d82a346ced6bbf07bdb523f1b , < da9b0ae47f084014b1e4b3f31f70a0defd047ff3 (git)
Affected: 2d07dc79fe04a43d82a346ced6bbf07bdb523f1b , < 788dbca056a8783ec063da3c9d49a3a71c76c283 (git)
Affected: 2d07dc79fe04a43d82a346ced6bbf07bdb523f1b , < 9593172d93b9f91c362baec4643003dc29802929 (git)
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Linux Linux Affected: 4.2
Unaffected: 0 , < 4.2 (semver)
Unaffected: 5.4.291 , ≤ 5.4.* (semver)
Unaffected: 5.10.235 , ≤ 5.10.* (semver)
Unaffected: 5.15.179 , ≤ 5.15.* (semver)
Unaffected: 6.1.130 , ≤ 6.1.* (semver)
Unaffected: 6.6.80 , ≤ 6.6.* (semver)
Unaffected: 6.12.17 , ≤ 6.12.* (semver)
Unaffected: 6.13.5 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem Affected: 0 , < * (custom)
guessed Create a notification for this product.
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngeneve: Fix use-after-free in geneve_find_dev().\n\nsyzkaller reported a use-after-free in geneve_find_dev() [0]\nwithout repro.\n\ngeneve_configure() links struct geneve_dev.next to\nnet_generic(net, geneve_net_id)-\u003egeneve_list.\n\nThe net here could differ from dev_net(dev) if IFLA_NET_NS_PID,\nIFLA_NET_NS_FD, or IFLA_TARGET_NETNSID is set.\n\nWhen dev_net(dev) is dismantled, geneve_exit_batch_rtnl() finally\ncalls unregister_netdevice_queue() for each dev in the netns,\nand later the dev is freed.\n\nHowever, its geneve_dev.next is still linked to the backend UDP\nsocket netns.\n\nThen, use-after-free will occur when another geneve dev is created\nin the netns.\n\nLet\u0027s call geneve_dellink() instead in geneve_destroy_tunnels().\n\n[0]:\nBUG: KASAN: slab-use-after-free in geneve_find_dev drivers/net/geneve.c:1295 [inline]\nBUG: KASAN: slab-use-after-free in geneve_configure+0x234/0x858 drivers/net/geneve.c:1343\nRead of size 2 at addr ffff000054d6ee24 by task syz.1.4029/13441\n\nCPU: 1 UID: 0 PID: 13441 Comm: syz.1.4029 Not tainted 6.13.0-g0ad9617c78ac #24 dc35ca22c79fb82e8e7bc5c9c9adafea898b1e3d\nHardware name: linux,dummy-virt (DT)\nCall trace:\n show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:466 (C)\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0x16c/0x6f0 mm/kasan/report.c:489\n kasan_report+0xc0/0x120 mm/kasan/report.c:602\n __asan_report_load2_noabort+0x20/0x30 mm/kasan/report_generic.c:379\n geneve_find_dev drivers/net/geneve.c:1295 [inline]\n geneve_configure+0x234/0x858 drivers/net/geneve.c:1343\n geneve_newlink+0xb8/0x128 drivers/net/geneve.c:1634\n rtnl_newlink_create+0x23c/0x868 net/core/rtnetlink.c:3795\n __rtnl_newlink net/core/rtnetlink.c:3906 [inline]\n rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021\n rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911\n netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543\n rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938\n netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]\n netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1348\n netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1892\n sock_sendmsg_nosec net/socket.c:713 [inline]\n __sock_sendmsg net/socket.c:728 [inline]\n ____sys_sendmsg+0x410/0x6f8 net/socket.c:2568\n ___sys_sendmsg+0x178/0x1d8 net/socket.c:2622\n __sys_sendmsg net/socket.c:2654 [inline]\n __do_sys_sendmsg net/socket.c:2659 [inline]\n __se_sys_sendmsg net/socket.c:2657 [inline]\n __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2657\n __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]\n invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49\n el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132\n do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151\n el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744\n el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762\n el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600\n\nAllocated by task 13247:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x30/0x68 mm/kasan/common.c:68\n kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568\n poison_kmalloc_redzone mm/kasan/common.c:377 [inline]\n __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394\n kasan_kmalloc include/linux/kasan.h:260 [inline]\n __do_kmalloc_node mm/slub.c:4298 [inline]\n __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4304\n __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:645\n alloc_netdev_mqs+0xb8/0x11a0 net/core/dev.c:11470\n rtnl_create_link+0x2b8/0xb50 net/core/rtnetlink.c:3604\n rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3780\n __rtnl_newlink net/core/rtnetlink.c:3906 [inline]\n rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021\n rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911\n netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543\n rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938\n netlink_unicast_kernel net/netlink/af_n\n---truncated---"
        }
      ],
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              "value": "AV:L - The vulnerability is reached only through RTM_NEWLINK rtnetlink messages sent on an AF_NETLINK socket, requiring local system access. The geneve_list is used solely by the control plane (geneve_configure/geneve_dellink), never by the packet receive path, so no remote packet can trigger it.\nAC:L - The attacker deterministically creates both network namespaces, creates the geneve device cross-netns, destroys the device-owning netns, then creates a second geneve device to dereference the stale list entry \u2014 no race must be won and the dangling pointer persists indefinitely, allowing unhurried heap grooming of the freed 4096-byte slab object.\nPR:L - CAP_NET_ADMIN is required in the owning user namespaces of both netns, but an unprivileged user obtains exactly that with `unshare -Urn` plus a nested `unshare -n`, since both namespaces are owned by their own user_ns and the checks are ns_capable-based. The geneve module is autoloaded on demand from the same unprivileged rtnl_newlink path.\nUI:N - The full sequence is performed by the attacker\u0027s own processes via netlink and namespace file descriptors, with no action by any other user.\nS:U - The use-after-free corrupts kernel heap state and is exploited for kernel privilege escalation within the same security authority; no hypervisor, IOMMU, or other authority boundary is crossed.\nC:H - The stale list entry points into a freed kmalloc-cg-4k object the attacker can reallocate and fill, so the list traversal in geneve_find_dev() follows an attacker-controlled `next` pointer and reads arbitrary kernel addresses, with the -EBUSY/-EPERM/success result acting as a disclosure oracle.\nI:H - Later list_del()/list_add() operations on the corrupted geneve_list write through attacker-controlled prev/next pointers, yielding a classic unlink write-what-where primitive suitable for control-flow hijacking and privilege escalation.\nA:H - The bug is a confirmed slab use-after-free (KASAN slab-use-after-free reported by syzkaller) that reliably corrupts a kernel linked list, causing oops or panic even without successful exploitation."
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          "url": "https://git.kernel.org/stable/c/9593172d93b9f91c362baec4643003dc29802929"
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngeneve: Fix use-after-free in geneve_find_dev().\n\nsyzkaller reported a use-after-free in geneve_find_dev() [0]\nwithout repro.\n\ngeneve_configure() links struct geneve_dev.next to\nnet_generic(net, geneve_net_id)-\u003egeneve_list.\n\nThe net here could differ from dev_net(dev) if IFLA_NET_NS_PID,\nIFLA_NET_NS_FD, or IFLA_TARGET_NETNSID is set.\n\nWhen dev_net(dev) is dismantled, geneve_exit_batch_rtnl() finally\ncalls unregister_netdevice_queue() for each dev in the netns,\nand later the dev is freed.\n\nHowever, its geneve_dev.next is still linked to the backend UDP\nsocket netns.\n\nThen, use-after-free will occur when another geneve dev is created\nin the netns.\n\nLet\u0027s call geneve_dellink() instead in geneve_destroy_tunnels().\n\n[0]:\nBUG: KASAN: slab-use-after-free in geneve_find_dev drivers/net/geneve.c:1295 [inline]\nBUG: KASAN: slab-use-after-free in geneve_configure+0x234/0x858 drivers/net/geneve.c:1343\nRead of size 2 at addr ffff000054d6ee24 by task syz.1.4029/13441\n\nCPU: 1 UID: 0 PID: 13441 Comm: syz.1.4029 Not tainted 6.13.0-g0ad9617c78ac #24 dc35ca22c79fb82e8e7bc5c9c9adafea898b1e3d\nHardware name: linux,dummy-virt (DT)\nCall trace:\n show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:466 (C)\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0x16c/0x6f0 mm/kasan/report.c:489\n kasan_report+0xc0/0x120 mm/kasan/report.c:602\n __asan_report_load2_noabort+0x20/0x30 mm/kasan/report_generic.c:379\n geneve_find_dev drivers/net/geneve.c:1295 [inline]\n geneve_configure+0x234/0x858 drivers/net/geneve.c:1343\n geneve_newlink+0xb8/0x128 drivers/net/geneve.c:1634\n rtnl_newlink_create+0x23c/0x868 net/core/rtnetlink.c:3795\n __rtnl_newlink net/core/rtnetlink.c:3906 [inline]\n rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021\n rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911\n netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543\n rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938\n netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]\n netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1348\n netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1892\n sock_sendmsg_nosec net/socket.c:713 [inline]\n __sock_sendmsg net/socket.c:728 [inline]\n ____sys_sendmsg+0x410/0x6f8 net/socket.c:2568\n ___sys_sendmsg+0x178/0x1d8 net/socket.c:2622\n __sys_sendmsg net/socket.c:2654 [inline]\n __do_sys_sendmsg net/socket.c:2659 [inline]\n __se_sys_sendmsg net/socket.c:2657 [inline]\n __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2657\n __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]\n invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49\n el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132\n do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151\n el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744\n el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762\n el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600\n\nAllocated by task 13247:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x30/0x68 mm/kasan/common.c:68\n kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568\n poison_kmalloc_redzone mm/kasan/common.c:377 [inline]\n __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394\n kasan_kmalloc include/linux/kasan.h:260 [inline]\n __do_kmalloc_node mm/slub.c:4298 [inline]\n __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4304\n __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:645\n alloc_netdev_mqs+0xb8/0x11a0 net/core/dev.c:11470\n rtnl_create_link+0x2b8/0xb50 net/core/rtnetlink.c:3604\n rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3780\n __rtnl_newlink net/core/rtnetlink.c:3906 [inline]\n rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021\n rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911\n netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543\n rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938\n netlink_unicast_kernel net/netlink/af_n\n---truncated---"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: geneve: Se corrige el problema de uso despu\u00e9s de la liberaci\u00f3n en geneve_find_dev(). syzkaller report\u00f3 un problema de uso despu\u00e9s de la liberaci\u00f3n en geneve_find_dev() [0] sin reproducci\u00f3n. geneve_configure() vincula la estructura geneve_dev.next con net_generic(net, geneve_net_id)-\u0026gt;geneve_list. La red aqu\u00ed podr\u00eda diferir de dev_net(dev) si se configura IFLA_NET_NS_PID, IFLA_NET_NS_FD o IFLA_TARGET_NETNSID. Al desmantelar dev_net(dev), geneve_exit_batch_rtnl() finalmente llama a unregister_netdevice_queue() para cada dispositivo en la red, y posteriormente se libera el dispositivo. Sin embargo, su geneve_dev.next a\u00fan est\u00e1 vinculado a la red del socket UDP del backend. Entonces, se producir\u00e1 un \"use-after-free\" al crear otro \"geneve dev\" en la red. En su lugar, llamaremos a \"geneve_dellink()\" en \"geneve_destroy_tunnels()\". [0]: ERROR: KASAN: slab-use-after-free in geneve_find_dev drivers/net/geneve.c:1295 [inline] BUG: KASAN: slab-use-after-free in geneve_configure+0x234/0x858 drivers/net/geneve.c:1343 Read of size 2 at addr ffff000054d6ee24 by task syz.1.4029/13441 CPU: 1 UID: 0 PID: 13441 Comm: syz.1.4029 Not tainted 6.13.0-g0ad9617c78ac #24 dc35ca22c79fb82e8e7bc5c9c9adafea898b1e3d Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x16c/0x6f0 mm/kasan/report.c:489 kasan_report+0xc0/0x120 mm/kasan/report.c:602 __asan_report_load2_noabort+0x20/0x30 mm/kasan/report_generic.c:379 geneve_find_dev drivers/net/geneve.c:1295 [inline] geneve_configure+0x234/0x858 drivers/net/geneve.c:1343 geneve_newlink+0xb8/0x128 drivers/net/geneve.c:1634 rtnl_newlink_create+0x23c/0x868 net/core/rtnetlink.c:3795 __rtnl_newlink net/core/rtnetlink.c:3906 [inline] rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:713 [inline] __sock_sendmsg net/socket.c:728 [inline] ____sys_sendmsg+0x410/0x6f8 net/socket.c:2568 ___sys_sendmsg+0x178/0x1d8 net/socket.c:2622 __sys_sendmsg net/socket.c:2654 [inline] __do_sys_sendmsg net/socket.c:2659 [inline] __se_sys_sendmsg net/socket.c:2657 [inline] __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2657 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151 el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600 Allocated by task 13247: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x68 mm/kasan/common.c:68 kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4298 [inline] __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4304 __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:645 alloc_netdev_mqs+0xb8/0x11a0 net/core/dev.c:11470 rtnl_create_link+0x2b8/0xb50 net/core/rtnetlink.c:3604 rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3780 __rtnl_newlink net/core/rtnetlink.c:3906 [inline] rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938 netlink_unicast_kernel net/netlink/af_n ---truncado---"
          }
        ],
        "id": "CVE-2025-21858",
        "lastModified": "2026-06-17T08:44:27.720",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "nvd@nist.gov",
              "type": "Primary"
            },
            {
              "cvssData": {
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                  "value": "AV:L - The vulnerability is reached only through RTM_NEWLINK rtnetlink messages sent on an AF_NETLINK socket, requiring local system access. The geneve_list is used solely by the control plane (geneve_configure/geneve_dellink), never by the packet receive path, so no remote packet can trigger it.\nAC:L - The attacker deterministically creates both network namespaces, creates the geneve device cross-netns, destroys the device-owning netns, then creates a second geneve device to dereference the stale list entry \u2014 no race must be won and the dangling pointer persists indefinitely, allowing unhurried heap grooming of the freed 4096-byte slab object.\nPR:L - CAP_NET_ADMIN is required in the owning user namespaces of both netns, but an unprivileged user obtains exactly that with `unshare -Urn` plus a nested `unshare -n`, since both namespaces are owned by their own user_ns and the checks are ns_capable-based. The geneve module is autoloaded on demand from the same unprivileged rtnl_newlink path.\nUI:N - The full sequence is performed by the attacker\u0027s own processes via netlink and namespace file descriptors, with no action by any other user.\nS:U - The use-after-free corrupts kernel heap state and is exploited for kernel privilege escalation within the same security authority; no hypervisor, IOMMU, or other authority boundary is crossed.\nC:H - The stale list entry points into a freed kmalloc-cg-4k object the attacker can reallocate and fill, so the list traversal in geneve_find_dev() follows an attacker-controlled `next` pointer and reads arbitrary kernel addresses, with the -EBUSY/-EPERM/success result acting as a disclosure oracle.\nI:H - Later list_del()/list_add() operations on the corrupted geneve_list write through attacker-controlled prev/next pointers, yielding a classic unlink write-what-where primitive suitable for control-flow hijacking and privilege escalation.\nA:H - The bug is a confirmed slab use-after-free (KASAN slab-use-after-free reported by syzkaller) that reliably corrupts a kernel linked list, causing oops or panic even without successful exploitation."
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          "references": [
            {
              "url": "https://git.kernel.org/stable/c/d5e86e27de0936f3cb0a299ce519d993e9cf3886"
            },
            {
              "url": "https://git.kernel.org/stable/c/5a0538ac6826807d6919f6aecbb8996c2865af2c"
            },
            {
              "url": "https://git.kernel.org/stable/c/f74f6560146714241c6e167b03165ee77a86e316"
            },
            {
              "url": "https://git.kernel.org/stable/c/904e746b2e7fa952ab8801b303ce826a63153d78"
            },
            {
              "url": "https://git.kernel.org/stable/c/3ce92ca990cfac88a87c61df3cc0b5880e688ecf"
            },
            {
              "url": "https://git.kernel.org/stable/c/da9b0ae47f084014b1e4b3f31f70a0defd047ff3"
            },
            {
              "url": "https://git.kernel.org/stable/c/788dbca056a8783ec063da3c9d49a3a71c76c283"
            },
            {
              "url": "https://git.kernel.org/stable/c/9593172d93b9f91c362baec4643003dc29802929"
            }
          ],
          "title": "geneve: Fix use-after-free in geneve_find_dev().",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2025-21858",
        "datePublished": "2025-03-12T09:42:11.343Z",
        "dateReserved": "2024-12-29T08:45:45.780Z",
        "dateUpdated": "2026-08-05T11:54:57.165Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.