{"cve":{"cve_id":"CVE-2026-53259","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\nipv6: anycast: insert aca into global hash under idev->lock\n\nsyzbot reported a splat [1]: a slab-use-after-free in\nipv6_chk_acast_addr(), which walks the global inet6_acaddr_lst[] hash\nunder RCU and dereferences a struct ifacaddr6 that has already been\nfreed while still linked in the hash, so a later reader walks into a\ndangling node.\n\nIn __ipv6_dev_ac_inc() the aca is allocated with refcount 1, then\naca_get() bumps it to 2 to keep it alive across the unlocked region.\nIt is published to idev->ac_list under idev->lock, but\nipv6_add_acaddr_hash() runs after write_unlock_bh(). A concurrent\nteardown (ipv6_ac_destroy_dev() from addrconf_ifdown(), under RTNL)\ncan slip into that window:\n\n  CPU0 __ipv6_dev_ac_inc           CPU1 ipv6_ac_destroy_dev (RTNL)\n  ------------------------------   ------------------------------------\n  aca_alloc()              refcnt 1\n  aca_get()               refcnt 2\n  write_lock_bh(idev->lock)\n    add aca to ac_list\n  write_unlock_bh(idev->lock)\n                                   write_lock_bh(idev->lock)\n                                     pull aca off ac_list\n                                   write_unlock_bh(idev->lock)\n                                   ipv6_del_acaddr_hash(aca)\n                                     hlist_del_init_rcu() is a no-op,\n                                     aca is not in the hash yet\n                                   aca_put()           refcnt 2->1\n  ipv6_add_acaddr_hash(aca)\n    aca now inserted into the hash\n  aca_put()                refcnt 1->0\n    call_rcu(aca_free_rcu) -> kfree(aca)\n\nThe hash removal becomes a no-op because the insertion has not\nhappened yet, so once CPU0 inserts and drops the last reference, the\naca is freed while still linked in inet6_acaddr_lst[], and readers\ndereference freed memory after the slab slot is reused.\n\nThis window opened once RTNL stopped serializing the join path against\ndevice teardown. Move ipv6_add_acaddr_hash() inside the idev->lock\nsection so the ac_list and hash insertions are atomic with respect to\nteardown: a racing remover now either misses the aca entirely or finds\nit in both lists.\n\nacaddr_hash_lock is now nested under idev->lock, which is acquired in\nsoftirq context, so switch all acaddr_hash_lock sites to spin_lock_bh()\nto avoid the irq lock inversion reported in [2].\n\n[1] https://syzkaller.appspot.com/bug?extid=a01df04303c131efbf3a\n[2] https://lore.kernel.org/netdev/6a194ef7.ba3b1513.1890b4.0000.GAE@google.com/","published_at":"2026-06-25T08:39:48.571000Z","last_modified_at":null,"cvss_v3_score":7.8,"cvss_v3_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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/15be7e9fdbff831fb3e89b83cc337a4f85ad3310","https://git.kernel.org/stable/c/3a967c498baa976b11d4800dda224c507416e97c","https://git.kernel.org/stable/c/f723ccaff2fb72b71ae8a9fd283f0dee4d9ae7a3"],"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":"2026-06-28T17:55:28.590503Z","updated_at":"2026-06-28T23:30:51.545322Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"L","value_label":"Local"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"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":"eb1ac9ff6c4a5720b1a1476233be374c5dc44bff","version_start_inclusive":true,"version_end":"15be7e9fdbff831fb3e89b83cc337a4f85ad3310","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:eb1ac9ff6c4a5720b1a1476233be374c5dc44bff:15be7e9fdbff831fb3e89b83cc337a4f85ad3310"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"eb1ac9ff6c4a5720b1a1476233be374c5dc44bff","version_start_inclusive":true,"version_end":"3a967c498baa976b11d4800dda224c507416e97c","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:eb1ac9ff6c4a5720b1a1476233be374c5dc44bff:3a967c498baa976b11d4800dda224c507416e97c"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"eb1ac9ff6c4a5720b1a1476233be374c5dc44bff","version_start_inclusive":true,"version_end":"f723ccaff2fb72b71ae8a9fd283f0dee4d9ae7a3","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:eb1ac9ff6c4a5720b1a1476233be374c5dc44bff:f723ccaff2fb72b71ae8a9fd283f0dee4d9ae7a3"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"6.17","version_start_inclusive":true,"version_end":"6.17","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:6.17:6.17"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"0","version_start_inclusive":true,"version_end":"6.17","version_end_inclusive":false,"cpe23_uri":"cve5:linux:linux:0:6.17"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"6.18.36","version_start_inclusive":true,"version_end":"6.18.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:6.18.36:6.18.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"7.0.13","version_start_inclusive":true,"version_end":"7.0.*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:7.0.13:7.0.*"},{"vendor_slug":"linux","vendor_name":"Linux","product_slug":"linux","product_name":"Linux","version_start":"7.1","version_start_inclusive":true,"version_end":"*","version_end_inclusive":true,"cpe23_uri":"cve5:linux:linux:7.1:*"}],"exploit_refs":[],"news":[],"references":[{"url":"https://git.kernel.org/stable/c/15be7e9fdbff831fb3e89b83cc337a4f85ad3310","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/3a967c498baa976b11d4800dda224c507416e97c","source_type":"MISC","tags":[]},{"url":"https://git.kernel.org/stable/c/f723ccaff2fb72b71ae8a9fd283f0dee4d9ae7a3","source_type":"MISC","tags":[]}],"timeline":[{"type":"published","at":"2026-06-25T08:39:48.571000Z","label":"CVE published","source":null}]}