{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-50154", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-10-21T19:36:19.960Z", "datePublished": "2024-11-07T09:31:30.855Z", "dateUpdated": "2026-08-05T11:42:07.102Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:42:07.102Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().\n\nMartin KaFai Lau reported use-after-free [0] in reqsk_timer_handler().\n\n \"\"\"\n We are seeing a use-after-free from a bpf prog attached to\n trace_tcp_retransmit_synack. The program passes the req->sk to the\n bpf_sk_storage_get_tracing kernel helper which does check for null\n before using it.\n \"\"\"\n\nThe commit 83fccfc3940c (\"inet: fix potential deadlock in\nreqsk_queue_unlink()\") added timer_pending() in reqsk_queue_unlink() not\nto call del_timer_sync() from reqsk_timer_handler(), but it introduced a\nsmall race window.\n\nBefore the timer is called, expire_timers() calls detach_timer(timer, true)\nto clear timer->entry.pprev and marks it as not pending.\n\nIf reqsk_queue_unlink() checks timer_pending() just after expire_timers()\ncalls detach_timer(), TCP will miss del_timer_sync(); the reqsk timer will\ncontinue running and send multiple SYN+ACKs until it expires.\n\nThe reported UAF could happen if req->sk is close()d earlier than the timer\nexpiration, which is 63s by default.\n\nThe scenario would be\n\n 1. inet_csk_complete_hashdance() calls inet_csk_reqsk_queue_drop(),\n but del_timer_sync() is missed\n\n 2. reqsk timer is executed and scheduled again\n\n 3. req->sk is accept()ed and reqsk_put() decrements rsk_refcnt, but\n reqsk timer still has another one, and inet_csk_accept() does not\n clear req->sk for non-TFO sockets\n\n 4. sk is close()d\n\n 5. reqsk timer is executed again, and BPF touches req->sk\n\nLet's not use timer_pending() by passing the caller context to\n__inet_csk_reqsk_queue_drop().\n\nNote that reqsk timer is pinned, so the issue does not happen in most\nuse cases. [1]\n\n[0]\nBUG: KFENCE: use-after-free read in bpf_sk_storage_get_tracing+0x2e/0x1b0\n\nUse-after-free read at 0x00000000a891fb3a (in kfence-#1):\nbpf_sk_storage_get_tracing+0x2e/0x1b0\nbpf_prog_5ea3e95db6da0438_tcp_retransmit_synack+0x1d20/0x1dda\nbpf_trace_run2+0x4c/0xc0\ntcp_rtx_synack+0xf9/0x100\nreqsk_timer_handler+0xda/0x3d0\nrun_timer_softirq+0x292/0x8a0\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\nintel_idle_irq+0x5a/0xa0\ncpuidle_enter_state+0x94/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\n\nkfence-#1: 0x00000000a72cc7b6-0x00000000d97616d9, size=2376, cache=TCPv6\n\nallocated by task 0 on cpu 9 at 260507.901592s:\nsk_prot_alloc+0x35/0x140\nsk_clone_lock+0x1f/0x3f0\ninet_csk_clone_lock+0x15/0x160\ntcp_create_openreq_child+0x1f/0x410\ntcp_v6_syn_recv_sock+0x1da/0x700\ntcp_check_req+0x1fb/0x510\ntcp_v6_rcv+0x98b/0x1420\nipv6_list_rcv+0x2258/0x26e0\nnapi_complete_done+0x5b1/0x2990\nmlx5e_napi_poll+0x2ae/0x8d0\nnet_rx_action+0x13e/0x590\nirq_exit_rcu+0xf5/0x320\ncommon_interrupt+0x80/0x90\nasm_common_interrupt+0x22/0x40\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb\n\nfreed by task 0 on cpu 9 at 260507.927527s:\nrcu_core_si+0x4ff/0xf10\nirq_exit_rcu+0xf5/0x320\nsysvec_apic_timer_interrupt+0x6d/0x80\nasm_sysvec_apic_timer_interrupt+0x16/0x20\ncpuidle_enter_state+0xfb/0x273\ncpu_startup_entry+0x15e/0x260\nstart_secondary+0x8a/0x90\nsecondary_startup_64_no_verify+0xfa/0xfb" } ], "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 vulnerability lives in the TCP/DCCP connection-request path and is driven entirely by packets from a remote peer — a SYN arms the pinned reqsk timer, and a final ACK, RST, or crafted ICMP/ICMPv6 error races `inet_csk_reqsk_queue_drop()` against it. Any internet-facing listening TCP socket is reachable with no local access.\nAC:L - The attacker controls both sides of the race: it chooses when the timer is armed (SYN → `jiffies + TCP_TIMEOUT_INIT`, 1 s) and when the drop executes (ACK/RST/ICMP at t≈1 s), and can run thousands of connections in parallel to hit the window reliably. The `TIMER_PINNED` same-CPU argument is defeated by attacker-chosen droppers that run on a different CPU — ICMP errors via `tcp_req_err()`, plus `tcp_abort()` and `inet_twsk_purge()` in process/workqueue context.\nPR:N - The entire path is pre-authentication TCP three-way-handshake and ICMP error handling in the kernel network stack, executed before any application-level credential check. An unauthenticated remote host merely needs to connect to a listening port.\nUI:N - No victim action is required; the server's ordinary `accept()`/`close()` lifecycle completes the scenario, and the ICMP and RST droppers need no local activity at all.\nS:U - The corruption is confined to kernel memory within the same security authority — freed socket objects and listener accept-queue accounting. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is a use-after-free read of a freed 2376-byte `struct tcp_sock` (KFENCE-confirmed); `bpf_sk_storage_get()` reads `sk->sk_state` and follows the stale `sk->sk_bpf_storage` pointer, returning `sdata->data` to the caller. An attacker who grooms the reallocated slab object turns that into an arbitrary kernel read primitive.\nI:H - The same UAF yields a write primitive — with `BPF_SK_STORAGE_GET_F_CREATE` the helper performs `refcount_inc_not_zero(&sk->sk_refcnt)` and `bpf_local_storage_update()` against the freed/reallocated object, and per CVSS kernel guidance a use-after-free is treated as exploitable for control-flow hijacking. Independently, the double `atomic_dec(&queue->young)` persistently corrupts the listener's SYN-queue accounting.\nA:H - Dereferencing the freed socket oopses or panics the kernel, and the condition is remotely repeatable across many connections. Even without a crash, each hijacked request floods SYN+ACK retransmissions for ~63 s and the underflowed `young` counter permanently clamps `max_syn_ack_retries` to 2, degrading the listener for its remaining lifetime." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv4/inet_connection_sock.c" ], "versions": [ { "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "106e457953315e476b3642ef24be25ed862aaba3", "status": "affected", "versionType": "git" }, { "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "c964bf65f80a14288d767023a1b300b30f5b9cd0", "status": "affected", "versionType": "git" }, { "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "8459d61fbf24967839a70235165673148c7c7f17", "status": "affected", "versionType": "git" }, { "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "5071beb59ee416e8ab456ac8647a4dabcda823b1", "status": "affected", "versionType": "git" }, { "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "997ae8da14f1639ce6fb66a063dab54031cd61b3", "status": "affected", "versionType": "git" }, { "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "51e34db64f4e43c7b055ccf881b7f3e0c31bb26d", "status": "affected", "versionType": "git" }, { "version": "83fccfc3940c4a2db90fd7e7079f5b465cd8c6af", "lessThan": "e8c526f2bdf1845bedaf6a478816a3d06fa78b8f", "status": "affected", "versionType": "git" }, { "version": "d3a1196bfc462943694623412d8e03aaf172bdc1", "status": "affected", "versionType": "git" }, { "version": "4.1.11", "lessThan": "4.2", "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/inet_connection_sock.c" ], "versions": [ { "version": "4.2", "status": "affected" }, { "version": "0", "lessThan": "4.2", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.293", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.237", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.170", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.115", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.59", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.11.6", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12", "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": "4.2", "versionEndExcluding": "5.4.293" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.10.237" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.15.170" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.1.115" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.6.59" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.11.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.1.11" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/106e457953315e476b3642ef24be25ed862aaba3" }, { "url": "https://git.kernel.org/stable/c/c964bf65f80a14288d767023a1b300b30f5b9cd0" }, { "url": "https://git.kernel.org/stable/c/8459d61fbf24967839a70235165673148c7c7f17" }, { "url": "https://git.kernel.org/stable/c/5071beb59ee416e8ab456ac8647a4dabcda823b1" }, { "url": "https://git.kernel.org/stable/c/997ae8da14f1639ce6fb66a063dab54031cd61b3" }, { "url": "https://git.kernel.org/stable/c/51e34db64f4e43c7b055ccf881b7f3e0c31bb26d" }, { "url": "https://git.kernel.org/stable/c/e8c526f2bdf1845bedaf6a478816a3d06fa78b8f" } ], "title": "tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2024-50154", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2024-12-11T14:25:48.087506Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-12-11T14:58:32.999Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T22:26:13.271Z" } } ] } }