{ "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-2026-64593", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-64593", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-08-06T07:13:49.700Z", "updatedAt": "2026-08-17T04:58:15.319Z", "importedAt": "2026-10-24T01:58:25.636Z", "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": "btrfs: do not trim a device which is not writeable", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: do not trim a device which is not writeable\n\n[BUG]\nThere is a bug report that btrfs/242 can randomly fail with the\nfollowing NULL pointer dereference:\n\n run fstests btrfs/242 at 2026-06-01 10:25:08\n BTRFS: device fsid d4d7f234-487c-4787-88e4-47a8b68c9874 devid 1 transid 9 /dev/sdc (8:32) scanned by mount (122609)\n BTRFS info (device sdc): first mount of filesystem d4d7f234-487c-4787-88e4-47a8b68c9874\n BTRFS info (device sdc): using crc32c checksum algorithm\n BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing\n BTRFS warning (device sdc): devid 2 uuid fbe72d72-3272-482d-80fb-ab88ed398192 is missing\n BTRFS info (device sdc): allowing degraded mounts\n BTRFS info (device sdc): turning on async discard\n BTRFS info (device sdc): enabling free space tree\n Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018\n user pgtable: 4k pages, 48-bit VAs, pgdp=000000013fd6b000\n CPU: 4 UID: 0 PID: 122625 Comm: fstrim Not tainted 7.0.10-2-default #1 PREEMPT(full) openSUSE Tumbleweed e9a5f6b24978fba3bf015a992f865837fdfff3dd\n Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20250812-19.fc42 08/12/2025\n pstate: 01400005 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)\n pc : btrfs_trim_fs+0x34c/0xa00 [btrfs]\n lr : btrfs_trim_fs+0x1f0/0xa00 [btrfs]\n Call trace:\n btrfs_trim_fs+0x34c/0xa00 [btrfs f02c1d570ceea621c69d302ba75dd61868083840] (P)\n btrfs_ioctl_fitrim+0xe8/0x178 [btrfs f02c1d570ceea621c69d302ba75dd61868083840]\n btrfs_ioctl+0xdd4/0x2bd8 [btrfs f02c1d570ceea621c69d302ba75dd61868083840]\n __arm64_sys_ioctl+0xac/0x108\n invoke_syscall.constprop.0+0x5c/0xd0\n el0_svc_common.constprop.0+0x40/0xf0\n do_el0_svc+0x24/0x40\n el0_svc+0x40/0x1d0\n el0t_64_sync_handler+0xa0/0xe8\n el0t_64_sync+0x1b0/0x1b8\n Code: 17ffff83 f94017e0 f9002be0 f9402ea0 (f9400c00)\n ---[ end trace 0000000000000000 ]---\n\nAlso the reporter is very kind to test the following ASSERT() added to\nbtrfs_trim_free_extents_throttle():\n\n\tASSERT(device->bdev,\n\t \"devid=%llu path=%s dev_state=0x%lx\\n\",\n\t device->devid, btrfs_dev_name(device), device->dev_state);\n\nAnd it shows the following output:\n\n assertion failed: device->bdev, in extent-tree.c:6630 (devid=2 path=/dev/sdd dev_state=0x82)\n\nWhich means the device->bdev is NULL, and the dev_state is\nBTRFS_DEV_STATE_IN_FS_METADATA | BTRFS_DEV_STATE_ITEM_FOUND, without\nBTRFS_DEV_STATE_WRITEABLE flag set.\n\n[CAUSE]\nThe pc points to the following call chain:\n\n btrfs_trim_fs()\n |- btrfs_trim_free_extents()\n |- btrfs_trim_free_extents_throttle()\n |- bdev_max_discard_sectors(device->bdev)\n\nSo the NULL pointer dereference is caused by device->bdev being NULL.\n\nThis looks impossible by a quick glance, as just before calling\nbtrfs_trim_free_extents_throttle(), we have skipped any device that has\nBTRFS_DEV_STATE_MISSING flag set.\n\nHowever in this particular case, there is a window where the missing\ndevice is later re-scanned, causing btrfs to remove the\nBTRFS_DEV_STATE_MISSING flag:\n\n btrfs_control_ioctl()\n |- btrfs_scan_one_device()\n |- device_list_add()\n |- rcu_assign_pointer(device->name, name);\n | This updates the missing device's path to the new good path.\n |\n |- clear_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state)\n This removes the BTRFS_DEV_STATE_MISSING flag.\n\nThis allows the missing device to re-appear and clear the\nBTRFS_DEV_STATE_MISSING flag. However the device still does not have\nthe BTRFS_DEV_STATE_WRITEABLE flag set, nor is its bdev pointer updated.\n\nThe bdev pointer remains NULL, triggering the crash later.\n\n[FIX]\nThis is a big de-synchronization between BTRFS_DEV_STATE_MISSING and\ndevice->bdev pointer, and shows a gap in btrfs's re-appearing-device\nhandling.\n\nThe proper handling of re-appearing device will need quite some extra\nwork, which is out of the context of this small\n---truncated---", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "499f377f49f085ee4aa214c738e948e88626f39b", "status": "affected", "versionType": "git", "lessThan": "f41ae7e6664f3c4361129728f2c4d5f3ed995251" }, { "version": "499f377f49f085ee4aa214c738e948e88626f39b", "status": "affected", "versionType": "git", "lessThan": "210af872eafa0cf572a84cb303c0f9d2914c1226" }, { "version": "499f377f49f085ee4aa214c738e948e88626f39b", "status": "affected", "versionType": "git", "lessThan": "3d8fa4b828a86b33c60858e58aaab6df273ede05" }, { "version": "499f377f49f085ee4aa214c738e948e88626f39b", "status": "affected", "versionType": "git", "lessThan": "9c894159c5b8adc84072e3af0e55b0473a69564e" }, { "version": "499f377f49f085ee4aa214c738e948e88626f39b", "status": "affected", "versionType": "git", "lessThan": "02c903fc6fc7e16c5d1f22d18784f1208acf43e3" }, { "version": "499f377f49f085ee4aa214c738e948e88626f39b", "status": "affected", "versionType": "git", "lessThan": "7a64521802997257b144e6edfb4e278dbeb972dd" }, { "version": "499f377f49f085ee4aa214c738e948e88626f39b", "status": "affected", "versionType": "git", "lessThan": "b4af31b898a948e29861cb0bae734058f9a49d9b" }, { "version": "499f377f49f085ee4aa214c738e948e88626f39b", "status": "affected", "versionType": "git", "lessThan": "1b1937eb08f51319bf71575484cde2b8c517aedc" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.3", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.3" }, { "version": "5.10.261", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.212", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.178", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.145", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.96", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.39", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.4", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }