{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40257", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.182Z", "datePublished": "2025-12-04T16:08:18.433Z", "dateUpdated": "2026-08-05T12:08:57.025Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:57.025Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix a race in mptcp_pm_del_add_timer()\n\nmptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_timer)\nwhile another might have free entry already, as reported by syzbot.\n\nAdd RCU protection to fix this issue.\n\nAlso change confusing add_timer variable with stop_timer boolean.\n\nsyzbot report:\n\nBUG: KASAN: slab-use-after-free in __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616\nRead of size 4 at addr ffff8880311e4150 by task kworker/1:1/44\n\nCPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025\nWorkqueue: events mptcp_worker\nCall Trace:\n \n dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xca/0x240 mm/kasan/report.c:482\n kasan_report+0x118/0x150 mm/kasan/report.c:595\n __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616\n sk_stop_timer_sync+0x1b/0x90 net/core/sock.c:3631\n mptcp_pm_del_add_timer+0x283/0x310 net/mptcp/pm.c:362\n mptcp_incoming_options+0x1357/0x1f60 net/mptcp/options.c:1174\n tcp_data_queue+0xca/0x6450 net/ipv4/tcp_input.c:5361\n tcp_rcv_established+0x1335/0x2670 net/ipv4/tcp_input.c:6441\n tcp_v4_do_rcv+0x98b/0xbf0 net/ipv4/tcp_ipv4.c:1931\n tcp_v4_rcv+0x252a/0x2dc0 net/ipv4/tcp_ipv4.c:2374\n ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205\n ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239\n NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318\n NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318\n __netif_receive_skb_one_core net/core/dev.c:6079 [inline]\n __netif_receive_skb+0x143/0x380 net/core/dev.c:6192\n process_backlog+0x31e/0x900 net/core/dev.c:6544\n __napi_poll+0xb6/0x540 net/core/dev.c:7594\n napi_poll net/core/dev.c:7657 [inline]\n net_rx_action+0x5f7/0xda0 net/core/dev.c:7784\n handle_softirqs+0x22f/0x710 kernel/softirq.c:622\n __do_softirq kernel/softirq.c:656 [inline]\n __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302\n mptcp_pm_send_ack net/mptcp/pm.c:210 [inline]\n mptcp_pm_addr_send_ack+0x41f/0x500 net/mptcp/pm.c:-1\n mptcp_pm_worker+0x174/0x320 net/mptcp/pm.c:1002\n mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762\n process_one_work kernel/workqueue.c:3263 [inline]\n process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346\n worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427\n kthread+0x711/0x8a0 kernel/kthread.c:463\n ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \n\nAllocated by task 44:\n kasan_save_stack mm/kasan/common.c:56 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n poison_kmalloc_redzone mm/kasan/common.c:400 [inline]\n __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417\n kasan_kmalloc include/linux/kasan.h:262 [inline]\n __kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5748\n kmalloc_noprof include/linux/slab.h:957 [inline]\n mptcp_pm_alloc_anno_list+0x104/0x460 net/mptcp/pm.c:385\n mptcp_pm_create_subflow_or_signal_addr+0xf9d/0x1360 net/mptcp/pm_kernel.c:355\n mptcp_pm_nl_fully_established net/mptcp/pm_kernel.c:409 [inline]\n __mptcp_pm_kernel_worker+0x417/0x1ef0 net/mptcp/pm_kernel.c:1529\n mptcp_pm_worker+0x1ee/0x320 net/mptcp/pm.c:1008\n mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762\n process_one_work kernel/workqueue.c:3263 [inline]\n process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346\n worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427\n kthread+0x711/0x8a0 kernel/kthread.c:463\n ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n\nFreed by task 6630:\n kasan_save_stack mm/kasan/common.c:56 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587\n kasan_save_free_info mm/kasan/kasan.h:406 [inline]\n poison_slab_object m\n---truncated---" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The use-after-free is dereferenced inside `mptcp_incoming_options()` while parsing an MPTCP ADD_ADDR echo option received from a remote peer (`tcp_v4_rcv → tcp_rcv_established → tcp_data_queue → mptcp_incoming_options → mptcp_pm_del_add_timer`), as shown verbatim in the syzbot stack. Any remote MPTCP peer of an internet-facing MPTCP-enabled server reaches this code with ordinary TCP packets.\nAC:L - The attacker controls both sides of the race — the ADD_ADDR echo can be emitted at will and repeatedly to keep a thread parked in the unlocked window, while the freeing side (`FLUSH_ADDRS`/`DEL_ADDR`/userspace-PM `REMOVE`) is either driven by the PM daemon reacting to the attacker's own MPTCP address events or issued directly by a local attacker looping netlink calls. Both `mptcp_pm_del_add_timer()` callers are trivially invokable in a tight loop, so the window is hit reliably.\nPR:N - A remote MPTCP peer needs no credentials or privileges on the target — only an established MPTCP connection, whose keys are what `add_addr_hmac_valid()` checks. Even the netlink half of the race is only `GENL_UNS_ADMIN_PERM`, i.e. CAP_NET_ADMIN reachable by an unprivileged user via `unshare -Urn`, so no real privilege is required anywhere on the path.\nUI:N - Exploitation happens entirely in the kernel's TCP receive path and the MPTCP path-manager worker; no victim action, mount, or file open is needed.\nS:U - The corruption is confined to kernel slab memory and the compromised component is the kernel itself, so there is no crossing into a different security authority.\nC:H - The freed `mptcp_pm_add_entry` lives in a sprayable general kmalloc cache; after reclaim, `__timer_delete_sync()` reads attacker-groomed memory and a fired `mptcp_pm_add_timer()` re-announces `entry->addr` from the reclaimed object, leaking kernel heap contents onto the wire and yielding an arbitrary-read primitive via the confused `entry->sock` pointer.\nI:H - `__timer_delete_sync()` writes into the freed timer during detach, and a timer firing out of a reallocated object drives `sk_reset_timer()`/`__sock_put()` on a fully attacker-controlled `entry->sock` pointer — a wild-pointer write and refcount decrement suitable for heap grooming into control-flow hijack.\nA:H - KASAN confirms a slab-use-after-free in `__timer_delete_sync()`; unmitigated this reliably corrupts timer-base list state and oopses or panics the kernel, and the race can be re-triggered repeatedly from the network for a persistent denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/mptcp/pm.c" ], "versions": [ { "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8", "lessThan": "9be29f8e7ce4e147e56caac2c3a0ce3573cf9c17", "status": "affected", "versionType": "git" }, { "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8", "lessThan": "e2d1ad207174a7cd7903dd27a00db4b2dfa6c64b", "status": "affected", "versionType": "git" }, { "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8", "lessThan": "385ddc0f008f24d1e7d03be998b3a98a37bd29ff", "status": "affected", "versionType": "git" }, { "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8", "lessThan": "c602cc344b4b8d41515fec3ffa98457ac963ee12", "status": "affected", "versionType": "git" }, { "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8", "lessThan": "6d3275d4ca62e2c02e1b7e8cd32db59df91c14b7", "status": "affected", "versionType": "git" }, { "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8", "lessThan": "bbbd75346c8e6490b19c2ba90f38ea66ccf352b2", "status": "affected", "versionType": "git" }, { "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8", "lessThan": "426358d9be7ce3518966422f87b96f1bad27295f", "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/mptcp/pm.c" ], "versions": [ { "version": "5.10", "status": "affected" }, { "version": "0", "lessThan": "5.10", "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": "6.6.118", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.60", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.10", "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": "5.10", "versionEndExcluding": "5.10.247" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "5.15.197" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.1.159" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.6.118" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.12.60" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.17.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/9be29f8e7ce4e147e56caac2c3a0ce3573cf9c17" }, { "url": "https://git.kernel.org/stable/c/e2d1ad207174a7cd7903dd27a00db4b2dfa6c64b" }, { "url": "https://git.kernel.org/stable/c/385ddc0f008f24d1e7d03be998b3a98a37bd29ff" }, { "url": "https://git.kernel.org/stable/c/c602cc344b4b8d41515fec3ffa98457ac963ee12" }, { "url": "https://git.kernel.org/stable/c/6d3275d4ca62e2c02e1b7e8cd32db59df91c14b7" }, { "url": "https://git.kernel.org/stable/c/bbbd75346c8e6490b19c2ba90f38ea66ccf352b2" }, { "url": "https://git.kernel.org/stable/c/426358d9be7ce3518966422f87b96f1bad27295f" } ], "title": "mptcp: fix a race in mptcp_pm_del_add_timer()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-06-02T13:00:10.342Z" }, "affected": [ { "vendor": "Siemens", "product": "RUGGEDCOM RST2428P", "versions": [ { "status": "affected", "version": "0", "lessThan": "V4.0", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-253495.html" } ] } ] } }