{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-64593 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-64593 is a vulnerability in Linux, published on 6 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-64593 and fix it if it is affected.\n\nWhat it is: CVE-2026-64593 is a vulnerability in Linux, published on 6 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-64593 in the wild and no public exploit code.\n\nAffected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-64593/ (Markdown: https://insights.sbomify.com/CVE-2026-64593/index.md)","id":"CVE-2026-64593","markdown":"https://insights.sbomify.com/CVE-2026-64593/index.md","name":"CVE-2026-64593","record":{"aliases":["BELL-CVE-2026-64593","DEBIAN-CVE-2026-64593","GHSA-2hc3-vpvv-mwv3","UBUNTU-CVE-2026-64593"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A local attacker can trigger a kernel crash via a null pointer dereference in the btrfs filesystem when trimming a non-writable device.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"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-\u003ebdev,\n\t       \"devid=%llu path=%s dev_state=0x%lx\\n\",\n\t       device-\u003edevid, btrfs_dev_name(device), device-\u003edev_state);\n\nAnd it shows the following output:\n\n  assertion failed: device-\u003ebdev, in extent-tree.c:6630 (devid=2 path=/dev/sdd dev_state=0x82)\n\nWhich means the device-\u003ebdev 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-\u003ebdev)\n\nSo the NULL pointer dereference is caused by device-\u003ebdev 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-\u003ename, name);\n        |  This updates the missing device's path to the new good path.\n        |\n        |- clear_bit(BTRFS_DEV_STATE_MISSING, \u0026device-\u003edev_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-\u003ebdev 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---","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"btrfs: do not trim a device which is not writeable","id":"CVE-2026-64593","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"null_dereference","year":"2026"},"n_packages":0,"n_references":8,"next":{"headline":"usb: gadget: f_fs: initialize reset_work at allocation time","id":"CVE-2026-64594"},"packages":[],"prev":{"headline":"riscv: mm: Unconditionally sfence.vma for spurious fault","id":"CVE-2026-64592"},"products":["Linux"],"published":"2026-08-06","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-08-17","vendors":["Linux"]},"summary":"A local attacker can trigger a kernel crash via a null pointer dereference in the btrfs filesystem when trimming a non-writable device.","url":"https://insights.sbomify.com/CVE-2026-64593/"}