{
"threat_severity" : "Moderate",
"public_date" : "2026-05-27T00:00:00Z",
"bugzilla" : {
"description" : "kernel: btrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation",
"id" : "2481949",
"url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2481949"
},
"cvss3" : {
"cvss3_base_score" : "7.0",
"cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
"status" : "draft"
},
"cwe" : "CWE-1285",
"details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nbtrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocation\nI have been observing a number of systems aborting at\ninsert_dev_extents() in btrfs_create_pending_block_groups(). The\nfollowing is a sample stack trace of such an abort coming from forced\nchunk allocation (typically behind CONFIG_BTRFS_EXPERIMENTAL) but this\ncan theoretically happen to any DUP chunk allocation.\n[81.801] ------------[ cut here ]------------\n[81.801] BTRFS: Transaction aborted (error -17)\n[81.801] WARNING: fs/btrfs/block-group.c:2876 at btrfs_create_pending_block_groups+0x721/0x770 [btrfs], CPU#1: bash/319\n[81.802] Modules linked in: virtio_net btrfs xor zstd_compress raid6_pq null_blk\n[81.803] CPU: 1 UID: 0 PID: 319 Comm: bash Kdump: loaded Not tainted 6.19.0-rc6+ #319 NONE\n[81.803] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014\n[81.804] RIP: 0010:btrfs_create_pending_block_groups+0x723/0x770 [btrfs]\n[81.806] RSP: 0018:ffffa36241a6bce8 EFLAGS: 00010282\n[81.806] RAX: 000000000000000d RBX: ffff8e699921e400 RCX: 0000000000000000\n[81.807] RDX: 0000000002040001 RSI: 00000000ffffffef RDI: ffffffffc0608bf0\n[81.807] RBP: 00000000ffffffef R08: ffff8e69830f6000 R09: 0000000000000007\n[81.808] R10: ffff8e699921e5e8 R11: 0000000000000000 R12: ffff8e6999228000\n[81.808] R13: ffff8e6984d82000 R14: ffff8e69966a69c0 R15: ffff8e69aa47b000\n[81.809] FS: 00007fec6bdd9740(0000) GS:ffff8e6b1b379000(0000) knlGS:0000000000000000\n[81.809] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[81.810] CR2: 00005604833670f0 CR3: 0000000116679000 CR4: 00000000000006f0\n[81.810] Call Trace:\n[81.810] \n[81.810] __btrfs_end_transaction+0x3e/0x2b0 [btrfs]\n[81.811] btrfs_force_chunk_alloc_store+0xcd/0x140 [btrfs]\n[81.811] kernfs_fop_write_iter+0x15f/0x240\n[81.812] vfs_write+0x264/0x500\n[81.812] ksys_write+0x6c/0xe0\n[81.812] do_syscall_64+0x66/0x770\n[81.812] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n[81.813] RIP: 0033:0x7fec6be66197\n[81.814] RSP: 002b:00007fffb159dd30 EFLAGS: 00000202 ORIG_RAX: 0000000000000001\n[81.815] RAX: ffffffffffffffda RBX: 00007fec6bdd9740 RCX: 00007fec6be66197\n[81.815] RDX: 0000000000000002 RSI: 0000560483374f80 RDI: 0000000000000001\n[81.816] RBP: 0000560483374f80 R08: 0000000000000000 R09: 0000000000000000\n[81.816] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002\n[81.817] R13: 00007fec6bfb85c0 R14: 00007fec6bfb5ee0 R15: 00005604833729c0\n[81.817] \n[81.817] irq event stamp: 20039\n[81.818] hardirqs last enabled at (20047): [] __up_console_sem+0x52/0x60\n[81.818] hardirqs last disabled at (20056): [] __up_console_sem+0x37/0x60\n[81.819] softirqs last enabled at (19470): [] __irq_exit_rcu+0x96/0xc0\n[81.819] softirqs last disabled at (19463): [] __irq_exit_rcu+0x96/0xc0\n[81.820] ---[ end trace 0000000000000000 ]---\n[81.820] BTRFS: error (device dm-7 state A) in btrfs_create_pending_block_groups:2876: errno=-17 Object already exists\nInspecting these aborts with drgn, I observed a pattern of overlapping\nchunk_maps. Note how stripe 1 of the first chunk overlaps in physical\naddress with stripe 0 of the second chunk.\nPhysical Start Physical End Length Logical Type Stripe\n----------------------------------------------------------------------------------------------------\n0x0000000102500000 0x0000000142500000 1.0G 0x0000000641d00000 META|DUP 0/2\n0x0000000142500000 0x0000000182500000 1.0G 0x0000000641d00000 META|DUP 1/2\n0x0000000142500000 0x0000000182500000 1.0G 0x0000000601d00000 META|DUP 0/2\n0x0000000182500000 0x00000001c2500000 1.0G 0x0000000601d00000 META|DUP 1/2\nNow how could this possibly happen? All chunk allocation is\n---truncated---", "A flaw was found in the Linux kernel's btrfs filesystem. This issue occurs due to non-consecutive gaps in chunk allocation, leading to overlapping chunk maps. A local attacker could exploit this by triggering specific chunk allocation scenarios, potentially causing filesystem operations to abort and resulting in a denial of service (DoS)." ],
"package_state" : [ {
"product_name" : "Red Hat Enterprise Linux 10",
"fix_state" : "Affected",
"package_name" : "kernel",
"cpe" : "cpe:/o:redhat:enterprise_linux:10"
}, {
"product_name" : "Red Hat Enterprise Linux 6",
"fix_state" : "Out of support scope",
"package_name" : "kernel",
"cpe" : "cpe:/o:redhat:enterprise_linux:6"
}, {
"product_name" : "Red Hat Enterprise Linux 7",
"fix_state" : "Affected",
"package_name" : "kernel",
"cpe" : "cpe:/o:redhat:enterprise_linux:7"
}, {
"product_name" : "Red Hat Enterprise Linux 7",
"fix_state" : "Affected",
"package_name" : "kernel-rt",
"cpe" : "cpe:/o:redhat:enterprise_linux:7"
}, {
"product_name" : "Red Hat Enterprise Linux 8",
"fix_state" : "Not affected",
"package_name" : "kernel",
"cpe" : "cpe:/o:redhat:enterprise_linux:8"
}, {
"product_name" : "Red Hat Enterprise Linux 8",
"fix_state" : "Not affected",
"package_name" : "kernel-rt",
"cpe" : "cpe:/o:redhat:enterprise_linux:8"
}, {
"product_name" : "Red Hat Enterprise Linux 9",
"fix_state" : "Not affected",
"package_name" : "kernel",
"cpe" : "cpe:/o:redhat:enterprise_linux:9"
}, {
"product_name" : "Red Hat Enterprise Linux 9",
"fix_state" : "Not affected",
"package_name" : "kernel-rt",
"cpe" : "cpe:/o:redhat:enterprise_linux:9"
} ],
"references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-45934\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-45934\nhttps://lore.kernel.org/linux-cve-announce/2026052727-CVE-2026-45934-e159@gregkh/T" ],
"name" : "CVE-2026-45934",
"csaw" : false
}