CVE-2026-43338

{"id": "CVE-2026-43338", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-43338", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-11-06T15:36:04.486560Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "affected": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "affectedData": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "5d13a37bd5327220e13329943d1228acfbe5934a", "lessThan": "4ccd563214419cef14a54df9333ed655484e9dc8", "versionType": "git"}, {"status": "affected", "version": "5d13a37bd5327220e13329943d1228acfbe5934a", "lessThan": "320942ce316a17b104b5814db55e42a42c2442cf", "versionType": "git"}, {"status": "affected", "version": "5d13a37bd5327220e13329943d1228acfbe5934a", "lessThan": "bb6eb33c908edbbb4d92abdc0c6c87f21b4952e8", "versionType": "git"}, {"status": "affected", "version": "5d13a37bd5327220e13329943d1228acfbe5934a", "lessThan": "cf930a651eef6f8d915bf0ccd60c2045974f870c", "versionType": "git"}, {"status": "affected", "version": "5d13a37bd5327220e13329943d1228acfbe5934a", "lessThan": "386f5e16a383101a68e195c806b4eedb233cd1d3", "versionType": "git"}, {"status": "affected", "version": "5d13a37bd5327220e13329943d1228acfbe5934a", "lessThan": "f9a4e3015db1aeafbef407650eb8555445ca943e", "versionType": "git"}], "programFiles": ["fs/btrfs/ioctl.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "3.6"}, {"status": "unaffected", "version": "0", "lessThan": "3.6", "versionType": "semver"}, {"status": "unaffected", "version": "6.1.191", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.160", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.81", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.22", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "6.19.12", "versionType": "semver", "lessThanOrEqual": "6.19.*"}, {"status": "unaffected", "version": "7.0", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["fs/btrfs/ioctl.c"], "defaultStatus": "affected"}]}], "published": "2026-05-08T14:16:43.630", "references": [{"url": "https://git.kernel.org/stable/c/320942ce316a17b104b5814db55e42a42c2442cf", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/386f5e16a383101a68e195c806b4eedb233cd1d3", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/4ccd563214419cef14a54df9333ed655484e9dc8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/bb6eb33c908edbbb4d92abdc0c6c87f21b4952e8", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/cf930a651eef6f8d915bf0ccd60c2045974f870c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/f9a4e3015db1aeafbef407650eb8555445ca943e", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: reserve enough transaction items for qgroup ioctls\n\nCurrently our qgroup ioctls don't reserve any space, they just do a\ntransaction join, which does not reserve any space, neither for the quota\ntree updates nor for the delayed refs generated when updating the quota\ntree. The quota root uses the global block reserve, which is fine most of\nthe time since we don't expect a lot of updates to the quota root, or to\nbe too close to -ENOSPC such that other critical metadata updates need to\nresort to the global reserve.\n\nHowever this is not optimal, as not reserving proper space may result in a\ntransaction abort due to not reserving space for delayed refs and then\nabusing the use of the global block reserve.\n\nFor example, the following reproducer (which is unlikely to model any\nreal world use case, but just to illustrate the problem), triggers such a\ntransaction abort due to -ENOSPC when running delayed refs:\n\n $ cat test.sh\n #!/bin/bash\n\n DEV=/dev/nullb0\n MNT=/mnt/nullb0\n\n umount $DEV &> /dev/null\n # Limit device to 1G so that it's much faster to reproduce the issue.\n mkfs.btrfs -f -b 1G $DEV\n mount -o commit=600 $DEV $MNT\n\n fallocate -l 800M $MNT/filler\n btrfs quota enable $MNT\n\n for ((i = 1; i <= 400000; i++)); do\n btrfs qgroup create 1/$i $MNT\n done\n\n umount $MNT\n\nWhen running this, we can see in dmesg/syslog that a transaction abort\nhappened:\n\n [436.490] BTRFS error (device nullb0): failed to run delayed ref for logical 30408704 num_bytes 16384 type 176 action 1 ref_mod 1: -28\n [436.493] ------------[ cut here ]------------\n [436.494] BTRFS: Transaction aborted (error -28)\n [436.495] WARNING: fs/btrfs/extent-tree.c:2247 at btrfs_run_delayed_refs+0xd9/0x110 [btrfs], CPU#4: umount/2495372\n [436.497] Modules linked in: btrfs loop (...)\n [436.508] CPU: 4 UID: 0 PID: 2495372 Comm: umount Tainted: G W 6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full)\n [436.510] Tainted: [W]=WARN\n [436.511] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014\n [436.513] RIP: 0010:btrfs_run_delayed_refs+0xdf/0x110 [btrfs]\n [436.514] Code: 0f 82 ea (...)\n [436.518] RSP: 0018:ffffd511850b7d78 EFLAGS: 00010292\n [436.519] RAX: 00000000ffffffe4 RBX: ffff8f120dad37e0 RCX: 0000000002040001\n [436.520] RDX: 0000000000000002 RSI: 00000000ffffffe4 RDI: ffffffffc090fd80\n [436.522] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffffc04d1867\n [436.523] R10: ffff8f18dc1fffa8 R11: 0000000000000003 R12: ffff8f173aa89400\n [436.524] R13: 0000000000000000 R14: ffff8f173aa89400 R15: 0000000000000000\n [436.526] FS: 00007fe59045d840(0000) GS:ffff8f192e22e000(0000) knlGS:0000000000000000\n [436.527] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n [436.528] CR2: 00007fe5905ff2b0 CR3: 000000060710a002 CR4: 0000000000370ef0\n [436.530] Call Trace:\n [436.530] <TASK>\n [436.530] btrfs_commit_transaction+0x73/0xc00 [btrfs]\n [436.531] ? btrfs_attach_transaction_barrier+0x1e/0x70 [btrfs]\n [436.532] sync_filesystem+0x7a/0x90\n [436.533] generic_shutdown_super+0x28/0x180\n [436.533] kill_anon_super+0x12/0x40\n [436.534] btrfs_kill_super+0x12/0x20 [btrfs]\n [436.534] deactivate_locked_super+0x2f/0xb0\n [436.534] cleanup_mnt+0xea/0x180\n [436.535] task_work_run+0x58/0xa0\n [436.535] exit_to_user_mode_loop+0xed/0x480\n [436.536] ? __x64_sys_umount+0x68/0x80\n [436.536] do_syscall_64+0x2a5/0xf20\n [436.537] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n [436.537] RIP: 0033:0x7fe5906b6217\n [436.538] Code: 0d 00 f7 (...)\n [436.540] RSP: 002b:00007ffcd87a61f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6\n [436.541] RAX: 0000000000000000 RBX: 00005618b9ecadc8 RCX: 00007fe5906b6217\n [436.541] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005618b9ecb100\n [436.542] RBP: 0000000000000000 R08: 00007ffcd87a4fe0 R09: 00000000ffffffff\n [436.544] R10: 0000000000000103 R11: \n---truncated---"}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: btrfs: reservar suficientes elementos de transacci\u00f3n para los ioctls de qgroup Actualmente, nuestros ioctls de qgroup no reservan ning\u00fan espacio, simplemente realizan una uni\u00f3n de transacci\u00f3n, lo cual no reserva ning\u00fan espacio, ni para las actualizaciones del \u00e1rbol de cuotas ni para las referencias retrasadas generadas al actualizar el \u00e1rbol de cuotas. La ra\u00edz de cuotas utiliza la reserva de bloques global, lo cual est\u00e1 bien la mayor parte del tiempo ya que no esperamos muchas actualizaciones a la ra\u00edz de cuotas, o estar demasiado cerca de -ENOSPC de modo que otras actualizaciones cr\u00edticas de metadatos necesiten recurrir a la reserva global. Sin embargo, esto no es \u00f3ptimo, ya que no reservar el espacio adecuado puede resultar en un aborto de transacci\u00f3n debido a no reservar espacio para referencias retrasadas y luego abusar del uso de la reserva de bloques global. Por ejemplo, el siguiente reproductor (que es poco probable que modele cualquier caso de uso del mundo real, pero solo para ilustrar el problema), desencadena tal aborto de transacci\u00f3n debido a -ENOSPC al ejecutar referencias retrasadas: $ cat test.sh #!/bin/bash DEV=[SystemPath]b0 MNT=/mnt/nullb0 umount $DEV y > [SystemPath] # Limitar el dispositivo a 1G para que sea mucho m\u00e1s r\u00e1pido reproducir el problema. mkfs.btrfs -f -b 1G $DEV mount -o commit=600 $DEV $MNT fallocate -l 800M $MNT/filler btrfs quota enable $MNT for ((i = 1; i menor o igual que 400000; i++)); do btrfs qgroup create 1/$i $MNT done umount $MNT Al ejecutar esto, podemos ver en dmesg/syslog que ocurri\u00f3 un aborto de transacci\u00f3n: [436.490] BTRFS error (device nullb0): failed to run delayed ref for logical 30408704 num_bytes 16384 type 176 action 1 ref_mod 1: -28 [436.493] ------------[ cut here ]------------ [436.494] BTRFS: Transaction aborted (error -28) [436.495] WARNING: fs/btrfs/extent-tree.c:2247 at btrfs_run_delayed_refs+0xd9/0x110 [btrfs], CPU#4: umount/2495372 [436.497] Modules linked in: btrfs loop (...) [436.508] CPU: 4 UID: 0 PID: 2495372 Comm: umount Tainted: G W 6.19.0-rc8-btrfs-next-225+ #1 PREEMPT(full) [436.510] Tainted: [W]=WARN [436.511] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [436.513] RIP: 0010:btrfs_run_delayed_refs+0xdf/0x110 [btrfs] [436.514] Code: 0f 82 ea (...) [436.518] RSP: 0018:ffffd511850b7d78 EFLAGS: 00010292 [436.519] RAX: 00000000ffffffe4 RBX: ffff8f120dad37e0 RCX: 0000000002040001 [436.520] RDX: 0000000000000002 RSI: 00000000ffffffe4 RDI: ffffffffc090fd80 [436.522] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffffc04d1867 [436.523] R10: ffff8f18dc1fffa8 R11: 0000000000000003 R12: ffff8f173aa89400 [436.524] R13: 0000000000000000 R14: ffff8f173aa89400 R15: 0000000000000000 [436.526] FS: 00007fe59045d840(0000) GS:ffff8f192e22e000(0000) knlGS:0000000000000000 [436.527] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [436.528] CR2: 00007fe5905ff2b0 CR3: 000000060710a002 CR4: 0000000000370ef0 [436.530] Call Trace: [436.530] [TASK] [436.530] btrfs_commit_transaction+0x73/0xc00 [btrfs] [436.531] ? btrfs_attach_transaction_barrier+0x1e/0x70 [btrfs] [436.532] sync_filesystem+0x7a/0x90 [436.533] generic_shutdown_super+0x28/0x180 [436.533] kill_anon_super+0x12/0x40 [436.534] btrfs_kill_super+0x12/0x20 [btrfs] [436.534] deactivate_locked_super+0x2f/0xb0 [436.534] cleanup_mnt+0xea/0x180 [436.535] task_work_run+0x58/0xa0 [436.535] exit_to_user_mode_loop+0xed/0x480 [436.536] ? __x64_sys_umount+0x68/0x80 [436.536] do_syscall_64+0x2a5/0xf20 [436.537] entry_SYSCALL_64_after_hwframe+0x76/0x7e [436.537] RIP: 0033:0x 7fe5906b6217 [436.538] Code: 0d 00 f7 (...) [436.540] RSP: 002b:00007ffcd87a61f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [436.541] RAX: 0000000000000000 RBX: 00005618b9ecadc8 RCX: 00007fe5906b6217 [436.541] RDX: 0000000000000000 RSI: 00000000 --TRUNCADO--"}], "lastModified": "2026-11-11T20:10:00.273", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4F8E3FD1-29C1-4D95-8843-58B47FD38079", "versionEndExcluding": "6.12.81", "versionStartIncluding": "3.6"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C9DF8BCE-36D3-475D-9D21-19E4F02F9029", "versionEndExcluding": "6.18.22", "versionStartIncluding": "6.13"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0A2B9540-02D5-41B4-B16A-82AF66FD4F36", "versionEndExcluding": "6.19.12", "versionStartIncluding": "6.19"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}