{"api_version":"1","generated_at":"2026-08-22T08:52:40+00:00","cve":"CVE-2026-74307","urls":{"html":"https://cve.report/CVE-2026-74307","api":"https://cve.report/api/cve/CVE-2026-74307.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74307","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74307"},"summary":{"title":"ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: validate donor file superblock early in EXT4_IOC_MOVE_EXT\n\nReject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not\nbelong to the same superblock as the original file.  Currently, this\nvalidation is performed inside ext4_move_extents() by\nmext_check_validity(), but only after lock_two_nondirectories() has\nalready acquired the inode locks.  When the donor fd refers to a file\non a different filesystem (e.g., overlayfs), this late validation\ncreates a circular lock dependency:\n\n  CPU0 (overlayfs write)            CPU1 (ext4 ioctl)\n  ----                              ----\n  inode_lock(ovl_inode)\n                                    mnt_want_write_file(filp)\n                                      sb_start_write(ext4_sb)   [sb_writers]\n    backing_file_write_iter()\n      vfs_iter_write(real_file)\n        file_start_write(real_file)\n          sb_start_write(ext4_sb)   [blocked by freeze]\n                                    lock_two_nondirectories()\n                                      inode_lock(ovl_inode)     [blocked]\n\nWith a concurrent freeze operation holding sb_writers write side, this\nforms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits\nfor CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock.\n\nSince EXT4_IOC_MOVE_EXT exchanges physical extents between two files,\nit fundamentally requires both files to reside on the same ext4\nfilesystem.  Moving the superblock check before any lock acquisition\nis both semantically correct and eliminates the circular dependency\nby ensuring that cross-filesystem donor fds are rejected before\nsb_writers or inode locks are taken.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:22:30","updated_at":"2026-08-17 06:19:24"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c","name":"https://git.kernel.org/stable/c/fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c143957520c6c9b5cd72e0de8b52b814f0c576fe","name":"https://git.kernel.org/stable/c/c143957520c6c9b5cd72e0de8b52b814f0c576fe","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/74796e886ca39fcb0d3fd36ea6a39c62784ab6fb","name":"https://git.kernel.org/stable/c/74796e886ca39fcb0d3fd36ea6a39c62784ab6fb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74307","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74307","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a 74796e886ca39fcb0d3fd36ea6a39c62784ab6fb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a c143957520c6c9b5cd72e0de8b52b814f0c576fe git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 3.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"74307","cve":"CVE-2026-74307","epss":"0.001660000","percentile":"0.062940000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:46"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/ext4/ioctl.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"74796e886ca39fcb0d3fd36ea6a39c62784ab6fb","status":"affected","version":"fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a","versionType":"git"},{"lessThan":"fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c","status":"affected","version":"fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a","versionType":"git"},{"lessThan":"c143957520c6c9b5cd72e0de8b52b814f0c576fe","status":"affected","version":"fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/ext4/ioctl.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.18"},{"lessThan":"3.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.97","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.97","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"3.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"3.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: validate donor file superblock early in EXT4_IOC_MOVE_EXT\n\nReject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not\nbelong to the same superblock as the original file.  Currently, this\nvalidation is performed inside ext4_move_extents() by\nmext_check_validity(), but only after lock_two_nondirectories() has\nalready acquired the inode locks.  When the donor fd refers to a file\non a different filesystem (e.g., overlayfs), this late validation\ncreates a circular lock dependency:\n\n  CPU0 (overlayfs write)            CPU1 (ext4 ioctl)\n  ----                              ----\n  inode_lock(ovl_inode)\n                                    mnt_want_write_file(filp)\n                                      sb_start_write(ext4_sb)   [sb_writers]\n    backing_file_write_iter()\n      vfs_iter_write(real_file)\n        file_start_write(real_file)\n          sb_start_write(ext4_sb)   [blocked by freeze]\n                                    lock_two_nondirectories()\n                                      inode_lock(ovl_inode)     [blocked]\n\nWith a concurrent freeze operation holding sb_writers write side, this\nforms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits\nfor CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock.\n\nSince EXT4_IOC_MOVE_EXT exchanges physical extents between two files,\nit fundamentally requires both files to reside on the same ext4\nfilesystem.  Moving the superblock check before any lock acquisition\nis both semantically correct and eliminates the circular dependency\nby ensuring that cross-filesystem donor fds are rejected before\nsb_writers or inode locks are taken."}],"providerMetadata":{"dateUpdated":"2026-08-17T05:16:56.046Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/74796e886ca39fcb0d3fd36ea6a39c62784ab6fb"},{"url":"https://git.kernel.org/stable/c/fb52013cad9e9b7d3a6a14ea1bcd841e41da7c6c"},{"url":"https://git.kernel.org/stable/c/c143957520c6c9b5cd72e0de8b52b814f0c576fe"}],"title":"ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74307","datePublished":"2026-08-15T05:58:07.969Z","dateReserved":"2026-08-15T05:44:03.883Z","dateUpdated":"2026-08-17T05:16:56.046Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:22:30","lastModifiedDate":"2026-08-17 06:19:24","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74307","Ordinal":"1","Title":"ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT","CVE":"CVE-2026-74307","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74307","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: validate donor file superblock early in EXT4_IOC_MOVE_EXT\n\nReject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not\nbelong to the same superblock as the original file.  Currently, this\nvalidation is performed inside ext4_move_extents() by\nmext_check_validity(), but only after lock_two_nondirectories() has\nalready acquired the inode locks.  When the donor fd refers to a file\non a different filesystem (e.g., overlayfs), this late validation\ncreates a circular lock dependency:\n\n  CPU0 (overlayfs write)            CPU1 (ext4 ioctl)\n  ----                              ----\n  inode_lock(ovl_inode)\n                                    mnt_want_write_file(filp)\n                                      sb_start_write(ext4_sb)   [sb_writers]\n    backing_file_write_iter()\n      vfs_iter_write(real_file)\n        file_start_write(real_file)\n          sb_start_write(ext4_sb)   [blocked by freeze]\n                                    lock_two_nondirectories()\n                                      inode_lock(ovl_inode)     [blocked]\n\nWith a concurrent freeze operation holding sb_writers write side, this\nforms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits\nfor CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock.\n\nSince EXT4_IOC_MOVE_EXT exchanges physical extents between two files,\nit fundamentally requires both files to reside on the same ext4\nfilesystem.  Moving the superblock check before any lock acquisition\nis both semantically correct and eliminates the circular dependency\nby ensuring that cross-filesystem donor fds are rejected before\nsb_writers or inode locks are taken.","Type":"Description","Title":"ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT"}]}}}