{"cve":{"cve_id":"CVE-2026-52946","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":null,"epss_percentile":null,"epss_as_of":null,"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling\n\nA SOFTIRQ-safe to SOFTIRQ-unsafe lock order deadlock can occur in\nsend_sigio() and send_sigurg() when a process group receives a signal.\n\nWhen FASYNC is configured for a process group (PIDTYPE_PGID), both\nfunctions use read_lock(&tasklist_lock) to traverse the task list.\nHowever, they are frequently called from softirq context:\n- send_sigio() via input_inject_event -> kill_fasync\n- send_sigurg() via tcp_check_urg -> sk_send_sigurg (NET_RX_SOFTIRQ)\n\nThe deadlock is caused by the rwlock writer fairness mechanism:\n1. CPU 0 (process context) holds read_lock(&tasklist_lock) in do_wait().\n2. CPU 1 (process context) attempts write_lock(&tasklist_lock) in\n   fork() or exit() and spins, which blocks all new readers.\n3. CPU 0 is interrupted by a softirq (e.g., TCP URG packet reception).\n4. The softirq calls send_sigurg() and attempts to acquire\n   read_lock(&tasklist_lock), deadlocking because CPU 1 is waiting.\n\nSince PID hashing and do_each_pid_task() traversals are already\nRCU-protected, the read_lock on tasklist_lock is no longer strictly\nrequired for safe traversal. Fix this by replacing tasklist_lock with\nrcu_read_lock(), aligning the process group signaling path with the\nsingle-PID path. This also mitigates a potential remote denial of\nservice vector via TCP URG packets.\n\nLockdep splat:\n=====================================================\nWARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected\n[...]\nChain exists of:\n  &dev->event_lock --> &f_owner->lock --> tasklist_lock\n\nPossible interrupt unsafe locking scenario:\n       CPU0                    CPU1\n       ----                    ----\n  lock(tasklist_lock);\n                           local_irq_disable();\n                           lock(&dev->event_lock);\n                           lock(&f_owner->lock);\n  <Interrupt>\n    lock(&dev->event_lock);\n\n*** DEADLOCK ***","published_at":"2026-06-24T16:26:04.419000Z","last_modified_at":null,"cvss_v3_score":7.5,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":null,"nvd_references":["https://git.kernel.org/stable/c/54626335ea4174ab2d9a183b511d825f6765e47b","https://git.kernel.org/stable/c/897d6a7247739fb1528f98c575df4f2e5de7f994","https://git.kernel.org/stable/c/32dbd5ce4be3a3ed7e00f8af18795cc84fc50a33","https://git.kernel.org/stable/c/b5fa9e32fb6718f70c986ee14dd5d01b4846f331","https://git.kernel.org/stable/c/1bee417678f1135e35b25a37734db46aa94258d2","https://git.kernel.org/stable/c/20a93e397abe850c49b6fa0e8cc827b5f634a8f5","https://git.kernel.org/stable/c/bfcc8e8d8a495bb34cae9e620adfb75fb13a3954","https://git.kernel.org/stable/c/36c1b57b2ecf3c61ac93f5f07bd29b6f21e226ed"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-28T17:55:22.518073Z","updated_at":"2026-06-28T23:30:49.890169Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"N","value_label":"None"},{"metric":"I","name":"Integrity","value":"N","value_label":"None"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","version_start_inclusive":true,"version_end":"54626335ea4174ab2d9a183b511d825f6765e47b","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:1da177e4c3f41524e886b7f1b8a0c1fc7321cac2:54626335ea4174ab2d9a183b511d825f6765e47b"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","version_start_inclusive":true,"version_end":"897d6a7247739fb1528f98c575df4f2e5de7f994","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:1da177e4c3f41524e886b7f1b8a0c1fc7321cac2:897d6a7247739fb1528f98c575df4f2e5de7f994"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","version_start_inclusive":true,"version_end":"32dbd5ce4be3a3ed7e00f8af18795cc84fc50a33","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:1da177e4c3f41524e886b7f1b8a0c1fc7321cac2:32dbd5ce4be3a3ed7e00f8af18795cc84fc50a33"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","version_start_inclusive":true,"version_end":"b5fa9e32fb6718f70c986ee14dd5d01b4846f331","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:1da177e4c3f41524e886b7f1b8a0c1fc7321cac2:b5fa9e32fb6718f70c986ee14dd5d01b4846f331"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","version_start_inclusive":true,"version_end":"1bee417678f1135e35b25a37734db46aa94258d2","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:1da177e4c3f41524e886b7f1b8a0c1fc7321cac2:1bee417678f1135e35b25a37734db46aa94258d2"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","version_start_inclusive":true,"version_end":"20a93e397abe850c49b6fa0e8cc827b5f634a8f5","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:1da177e4c3f41524e886b7f1b8a0c1fc7321cac2:20a93e397abe850c49b6fa0e8cc827b5f634a8f5"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","version_start_inclusive":true,"version_end":"bfcc8e8d8a495bb34cae9e620adfb75fb13a3954","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:1da177e4c3f41524e886b7f1b8a0c1fc7321cac2:bfcc8e8d8a495bb34cae9e620adfb75fb13a3954"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","version_start_inclusive":true,"version_end":"36c1b57b2ecf3c61ac93f5f07bd29b6f21e226ed","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:1da177e4c3f41524e886b7f1b8a0c1fc7321cac2:36c1b57b2ecf3c61ac93f5f07bd29b6f21e226ed"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"5.10.259","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:5.10.259"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"5.15.210","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:5.15.210"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"6.1.176","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:6.1.176"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"6.6.143","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:6.6.143"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"6.12.94","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:6.12.94"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"6.18.36","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:6.18.36"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start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published","source":null}]}