{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90139","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.789Z","datePublished":"2026-09-17T16:06:37.179Z","dateUpdated":"2026-09-17T16:06:37.179Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-17T16:06:37.179Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: check for NULL root inode in fuse_fill_super_submount\n\nfuse_iget() can return NULL when its inode allocation fails, but\nfuse_fill_super_submount() passed the result straight to get_fuse_inode()\nand decremented fi->nlookup without checking it:\n\n        root = fuse_iget(sb, parent_fi->nodeid, ...);\n        fi = get_fuse_inode(root);\n        fi->nlookup--;\n\nInside fuse_iget() the inode allocation can fail and return NULL.  The\nsubmount root takes the iget5_locked() path, whose alloc_inode() can fail\nunder memory pressure (the auto-submount branch can fail the same way in\nnew_inode() or fuse_alloc_submount_lookup()):\n\n        inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set,\n                             &nodeid);\n        if (!inode)\n                return NULL;\n\nA NULL root makes get_fuse_inode() a container_of() on NULL and the\nnlookup decrement a write to a bogus address, oopsing the mount.  With\nCONFIG_KASAN the following null pointer dereference is reported when the\nroot inode allocation of an auto-submount fails (e.g. under memory\npressure):\n\n==================================================================\nBUG: KASAN: null-ptr-deref in fuse_get_tree_submount+0x656/0x8b0\nRead of size 8 at addr 00000000000002b0 by task ls/942\nCPU: 0 PID: 942 Comm: ls Tainted: G W 6.6 #15\nCall Trace:\n <TASK>\n fuse_get_tree_submount+0x656/0x8b0\n vfs_get_tree+0x48/0x140\n fc_mount+0x13/0x50\n fuse_dentry_automount+0x7a/0xb0\n __traverse_mounts+0xca/0x330\n step_into+0x339/0xac0\n path_lookupat+0xc5/0x2f0\n filename_lookup+0x163/0x2a0\n vfs_statx+0xd5/0x200\n do_statx+0x83/0xd0\n __x64_sys_statx+0xa0/0xc0\n do_syscall_64+0x37/0x90\n entry_SYSCALL_64_after_hwframe+0x78/0xe2\n </TASK>\n==================================================================\n\nReturn -ENOMEM instead; the caller tears down the partially built\nsuperblock on error, matching the other error returns in this\nfunction."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/fuse/inode.c"],"versions":[{"version":"1866d779d5d2abae59d304e809600ca3ca8d0071","lessThan":"17120c5bfb16808509ea18d7fab6027802d93eba","status":"affected","versionType":"git"},{"version":"1866d779d5d2abae59d304e809600ca3ca8d0071","lessThan":"e0b7f2922f6bd4c23cbddb7d1fc2bada570d27d1","status":"affected","versionType":"git"},{"version":"1866d779d5d2abae59d304e809600ca3ca8d0071","lessThan":"a5129155ca9fba40d77ff19ffead8244e88d6f9c","status":"affected","versionType":"git"},{"version":"1866d779d5d2abae59d304e809600ca3ca8d0071","lessThan":"509f4a09bae7f03c87f67f053648874a5e177867","status":"affected","versionType":"git"},{"version":"1866d779d5d2abae59d304e809600ca3ca8d0071","lessThan":"928f659a3e3650978a5b4829cc982324f72b474b","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/fuse/inode.c"],"versions":[{"version":"5.10","status":"affected"},{"version":"0","lessThan":"5.10","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.110","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.52","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.6","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/17120c5bfb16808509ea18d7fab6027802d93eba"},{"url":"https://git.kernel.org/stable/c/e0b7f2922f6bd4c23cbddb7d1fc2bada570d27d1"},{"url":"https://git.kernel.org/stable/c/a5129155ca9fba40d77ff19ffead8244e88d6f9c"},{"url":"https://git.kernel.org/stable/c/509f4a09bae7f03c87f67f053648874a5e177867"},{"url":"https://git.kernel.org/stable/c/928f659a3e3650978a5b4829cc982324f72b474b"}],"title":"fuse: check for NULL root inode in fuse_fill_super_submount","x_generator":{"engine":"bippy-1.2.0"}}}}