{"id":"AZL-102387","summary":"CVE-2026-90139 affecting package kernel 6.6.150.1-1","details":"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-\u003enlookup without checking it:\n\n        root = fuse_iget(sb, parent_fi-\u003enodeid, ...);\n        fi = get_fuse_inode(root);\n        fi-\u003enlookup--;\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 \u003cTASK\u003e\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 \u003c/TASK\u003e\n==================================================================\n\nReturn -ENOMEM instead; the caller tears down the partially built\nsuperblock on error, matching the other error returns in this\nfunction.","modified":"2026-09-18T14:15:30.226932519Z","published":"2026-09-17T17:17:06Z","upstream":["CVE-2026-90139"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90139"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102387.json"}}],"schema_version":"1.9.0"}