{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2025-21631",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-21631",
    "idYear": 2025,
    "status": "PUBLISHED",
    "publishedAt": "2025-01-19T10:17:49.439Z",
    "updatedAt": "2026-08-05T11:53:16.126Z",
    "importedAt": "2026-10-24T01:57:29.455Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "block, bfq: fix waker_bfqq UAF after bfq_split_bfqq()",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock, bfq: fix waker_bfqq UAF after bfq_split_bfqq()\n\nOur syzkaller report a following UAF for v6.6:\n\nBUG: KASAN: slab-use-after-free in bfq_init_rq+0x175d/0x17a0 block/bfq-iosched.c:6958\nRead of size 8 at addr ffff8881b57147d8 by task fsstress/232726\n\nCPU: 2 PID: 232726 Comm: fsstress Not tainted 6.6.0-g3629d1885222 #39\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x91/0xf0 lib/dump_stack.c:106\n print_address_description.constprop.0+0x66/0x300 mm/kasan/report.c:364\n print_report+0x3e/0x70 mm/kasan/report.c:475\n kasan_report+0xb8/0xf0 mm/kasan/report.c:588\n hlist_add_head include/linux/list.h:1023 [inline]\n bfq_init_rq+0x175d/0x17a0 block/bfq-iosched.c:6958\n bfq_insert_request.isra.0+0xe8/0xa20 block/bfq-iosched.c:6271\n bfq_insert_requests+0x27f/0x390 block/bfq-iosched.c:6323\n blk_mq_insert_request+0x290/0x8f0 block/blk-mq.c:2660\n blk_mq_submit_bio+0x1021/0x15e0 block/blk-mq.c:3143\n __submit_bio+0xa0/0x6b0 block/blk-core.c:639\n __submit_bio_noacct_mq block/blk-core.c:718 [inline]\n submit_bio_noacct_nocheck+0x5b7/0x810 block/blk-core.c:747\n submit_bio_noacct+0xca0/0x1990 block/blk-core.c:847\n __ext4_read_bh fs/ext4/super.c:205 [inline]\n ext4_read_bh+0x15e/0x2e0 fs/ext4/super.c:230\n __read_extent_tree_block+0x304/0x6f0 fs/ext4/extents.c:567\n ext4_find_extent+0x479/0xd20 fs/ext4/extents.c:947\n ext4_ext_map_blocks+0x1a3/0x2680 fs/ext4/extents.c:4182\n ext4_map_blocks+0x929/0x15a0 fs/ext4/inode.c:660\n ext4_iomap_begin_report+0x298/0x480 fs/ext4/inode.c:3569\n iomap_iter+0x3dd/0x1010 fs/iomap/iter.c:91\n iomap_fiemap+0x1f4/0x360 fs/iomap/fiemap.c:80\n ext4_fiemap+0x181/0x210 fs/ext4/extents.c:5051\n ioctl_fiemap.isra.0+0x1b4/0x290 fs/ioctl.c:220\n do_vfs_ioctl+0x31c/0x11a0 fs/ioctl.c:811\n __do_sys_ioctl fs/ioctl.c:869 [inline]\n __se_sys_ioctl+0xae/0x190 fs/ioctl.c:857\n do_syscall_x64 arch/x86/entry/common.c:51 [inline]\n do_syscall_64+0x70/0x120 arch/x86/entry/common.c:81\n entry_SYSCALL_64_after_hwframe+0x78/0xe2\n\nAllocated by task 232719:\n kasan_save_stack+0x22/0x50 mm/kasan/common.c:45\n kasan_set_track+0x25/0x30 mm/kasan/common.c:52\n __kasan_slab_alloc+0x87/0x90 mm/kasan/common.c:328\n kasan_slab_alloc include/linux/kasan.h:188 [inline]\n slab_post_alloc_hook mm/slab.h:768 [inline]\n slab_alloc_node mm/slub.c:3492 [inline]\n kmem_cache_alloc_node+0x1b8/0x6f0 mm/slub.c:3537\n bfq_get_queue+0x215/0x1f00 block/bfq-iosched.c:5869\n bfq_get_bfqq_handle_split+0x167/0x5f0 block/bfq-iosched.c:6776\n bfq_init_rq+0x13a4/0x17a0 block/bfq-iosched.c:6938\n bfq_insert_request.isra.0+0xe8/0xa20 block/bfq-iosched.c:6271\n bfq_insert_requests+0x27f/0x390 block/bfq-iosched.c:6323\n blk_mq_insert_request+0x290/0x8f0 block/blk-mq.c:2660\n blk_mq_submit_bio+0x1021/0x15e0 block/blk-mq.c:3143\n __submit_bio+0xa0/0x6b0 block/blk-core.c:639\n __submit_bio_noacct_mq block/blk-core.c:718 [inline]\n submit_bio_noacct_nocheck+0x5b7/0x810 block/blk-core.c:747\n submit_bio_noacct+0xca0/0x1990 block/blk-core.c:847\n __ext4_read_bh fs/ext4/super.c:205 [inline]\n ext4_read_bh_nowait+0x15a/0x240 fs/ext4/super.c:217\n ext4_read_bh_lock+0xac/0xd0 fs/ext4/super.c:242\n ext4_bread_batch+0x268/0x500 fs/ext4/inode.c:958\n __ext4_find_entry+0x448/0x10f0 fs/ext4/namei.c:1671\n ext4_lookup_entry fs/ext4/namei.c:1774 [inline]\n ext4_lookup.part.0+0x359/0x6f0 fs/ext4/namei.c:1842\n ext4_lookup+0x72/0x90 fs/ext4/namei.c:1839\n __lookup_slow+0x257/0x480 fs/namei.c:1696\n lookup_slow fs/namei.c:1713 [inline]\n walk_component+0x454/0x5c0 fs/namei.c:2004\n link_path_walk.part.0+0x773/0xda0 fs/namei.c:2331\n link_path_walk fs/namei.c:3826 [inline]\n path_openat+0x1b9/0x520 fs/namei.c:3826\n do_filp_open+0x1b7/0x400 fs/namei.c:3857\n do_sys_openat2+0x5dc/0x6e0 fs/open.c:1428\n do_sys_open fs/open.c:1443 [inline]\n __do_sys_openat fs/open.c:1459 [inline]\n __se_sys_openat fs/open.c:1454 [inline]\n __x64_sys_openat+0x148/0x200 fs/open.c:1454\n do_syscall_x64 arch/x86/entry/common.c:51 [inline]\n do_syscall_6\n---truncated---",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "63a07379fdb6c72450cb05294461c6016b8b7726",
              "status": "affected",
              "versionType": "git",
              "lessThan": "f587c1ac68956c4703857d650d9b1cd7bb2ac4d7"
            },
            {
              "version": "de0456460f2abf921e356ed2bd8da87a376680bd",
              "status": "affected",
              "versionType": "git",
              "lessThan": "2550149fcdf2934155ff625d76ad4e3d4b25bbc6"
            },
            {
              "version": "0780451f03bf518bc032a7c584de8f92e2d39d7f",
              "status": "affected",
              "versionType": "git",
              "lessThan": "be3eed59ac01f429ac10aaa46e26f653bcf581ab"
            },
            {
              "version": "1ba0403ac6447f2d63914fb760c44a3b19c44eaf",
              "status": "affected",
              "versionType": "git",
              "lessThan": "bc2aeb35ff167e0c6b0cedf0c96a5c41e6cba1ed"
            },
            {
              "version": "1ba0403ac6447f2d63914fb760c44a3b19c44eaf",
              "status": "affected",
              "versionType": "git",
              "lessThan": "fcede1f0a043ccefe9bc6ad57f12718e42f63f1d"
            },
            {
              "version": "0b8bda0ff17156cd3f60944527c9d8c9f99f1583",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "cae58d19121a70329cf971359e2518c93fec04fe",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "5.15.168",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "5.15.177"
            },
            {
              "version": "6.1.113",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.1.125"
            },
            {
              "version": "6.6.54",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.6.72"
            },
            {
              "version": "6.10.13",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.11"
            },
            {
              "version": "6.11.2",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.12"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "6.12",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "6.12"
            },
            {
              "version": "5.15.177",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.125",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.72",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.10",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.13",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}