{"id":"CVE-2026-89601","state":"PUBLISHED","title":"ext2: Fix lost inode updates for IS_SYNC inodes","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next2: Fix lost inode updates for IS_SYNC inodes\n\next2_setsize() and ext2_xattr_set2() had a construct like:\n\n\tif (IS_SYNC(inode)) {\n\t\tsync_inode_metadata(inode, 1);\n\t} else {\n\t\tmark_inode_dirty(inode);\n\t}\n\nwhich leads to lost inode updates for IS_SYNC inodes because\nsync_inode_metadata() does anything only if the inode is already dirty\nand hence inode updates may be simply lost. Fix the problem by\nunconditionally marking the inode dirty and *then* call\nsync_inode_metadata().","publishedAt":"2026-09-11T19:45:04.667Z","updatedAt":"2026-10-30T12:32:18.488Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"55e66d84b5272c425b324a2b247cdacacf1e10b9","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"b879565effd88fc119c2efea3f3868a9997ed9ba","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"e54de654423bee98d1ba50379b09daf97c7854a6","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"5481766125041e71662f2e32ee0e91ad5f4d07f4","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"5efb3350230fef831167740e69e6db2861101186","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"356984d1a5c32e94810cbb6c8dc7d8ff2d4d919a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext2/inode.c","fs/ext2/xattr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext2/inode.c","fs/ext2/xattr.c"]}],"references":["https://git.kernel.org/stable/c/55e66d84b5272c425b324a2b247cdacacf1e10b9","https://git.kernel.org/stable/c/b879565effd88fc119c2efea3f3868a9997ed9ba","https://git.kernel.org/stable/c/e54de654423bee98d1ba50379b09daf97c7854a6","https://git.kernel.org/stable/c/5481766125041e71662f2e32ee0e91ad5f4d07f4","https://git.kernel.org/stable/c/5efb3350230fef831167740e69e6db2861101186","https://git.kernel.org/stable/c/356984d1a5c32e94810cbb6c8dc7d8ff2d4d919a"],"weaknesses":[],"ingestedAt":"2026-10-30T12:50:04.827Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89601.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89601","state":"PUBLISHED","datePublished":"2026-09-11T19:45:04.667Z","dateUpdated":"2026-10-30T12:32:18.488Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.732Z"},"containers":{"cna":{"title":"ext2: Fix lost inode updates for IS_SYNC inodes","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\next2: Fix lost inode updates for IS_SYNC inodes\n\next2_setsize() and ext2_xattr_set2() had a construct like:\n\n\tif (IS_SYNC(inode)) {\n\t\tsync_inode_metadata(inode, 1);\n\t} else {\n\t\tmark_inode_dirty(inode);\n\t}\n\nwhich leads to lost inode updates for IS_SYNC inodes because\nsync_inode_metadata() does anything only if the inode is already dirty\nand hence inode updates may be simply lost. Fix the problem by\nunconditionally marking the inode dirty and *then* call\nsync_inode_metadata()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"55e66d84b5272c425b324a2b247cdacacf1e10b9","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"b879565effd88fc119c2efea3f3868a9997ed9ba","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"e54de654423bee98d1ba50379b09daf97c7854a6","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"5481766125041e71662f2e32ee0e91ad5f4d07f4","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"5efb3350230fef831167740e69e6db2861101186","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"356984d1a5c32e94810cbb6c8dc7d8ff2d4d919a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext2/inode.c","fs/ext2/xattr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext2/inode.c","fs/ext2/xattr.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/55e66d84b5272c425b324a2b247cdacacf1e10b9"},{"url":"https://git.kernel.org/stable/c/b879565effd88fc119c2efea3f3868a9997ed9ba"},{"url":"https://git.kernel.org/stable/c/e54de654423bee98d1ba50379b09daf97c7854a6"},{"url":"https://git.kernel.org/stable/c/5481766125041e71662f2e32ee0e91ad5f4d07f4"},{"url":"https://git.kernel.org/stable/c/5efb3350230fef831167740e69e6db2861101186"},{"url":"https://git.kernel.org/stable/c/356984d1a5c32e94810cbb6c8dc7d8ff2d4d919a"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - nfsd SETATTR/SETXATTR and ksmbd truncate/EA handling call notify_change()/vfs_setxattr() into ext2_setattr()/ext2_xattr_set2() when an ext2 volume is NFS/SMB-exported (NAS and embedded USB-storage appliances, including sync-mounted disks); a remote client with write access therefore reaches the lost IS_SYNC inode update without a local shell.\nAC:L - The attacker can put the target in the IS_SYNC state at will (owner-writable FS_IOC_SETFLAGS/chattr +S, or a sync-mounted export) and then deterministically truncate or set/remove xattrs; sync_inode_metadata() skips a clean inode every time, with no race or memory layout outside attacker control.\nPR:L - The path is gated only by ordinary VFS write checks (inode_permission MAY_WRITE, xattr_permission for user.* xattrs, or inode_owner_or_capable() for FS_IOC_SETFLAGS); an unprivileged local user or a low-privilege NFS/SMB client with write access to a file suffices, and no init-namespace capability is required.\nUI:N - The attacker performs every step themselves (setting the SYNC flag, truncating or changing xattrs/ACLs, and driving inode reclaim); no separate victim action such as mounting a crafted image is required.\nS:U - Impact is confined to filesystem metadata and file data on the host that mounted the ext2 volume; this is not a VM escape, IOMMU bypass, or other cross-authority boundary.\nC:H - Removing the last xattr on an IS_SYNC inode frees the EA block without persisting i_file_acl=0, leaving a dangling on-disk pointer; after that block is reused, ext2_xattr_get() memcpy()s its contents to userspace when the header looks valid, so the filesystem-level UAF discloses other files' data.\nI:H - The lost i_file_acl update leaves the on-disk inode pointing at a freed EA block, so a later in-place xattr write can corrupt whatever reused that block, including other users' files and metadata; intended-durable IS_SYNC size/ctime/ACL updates can also fail to land, corrupting filesystem state.\nA:H - Reloading the stale i_file_acl and reading an invalid reused EA block calls ext2_error(), which panics on errors=panic and remounts the volume read-only on errors=remount-ro; the resulting filesystem inconsistency can also render files and the volume unavailable."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:32:18.488Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}