{"id":"AZL-100220","summary":"CVE-2026-89490 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix readdir position truncation on 32-bit kernels\n\nIn ocfs2_dir_foreach_blk_el(), the directory cookie position is\nrebuilt with\n\n\tctx-\u003epos = (ctx-\u003epos & ~(sb-\u003es_blocksize - 1)) | offset;\n\n`ctx-\u003epos` is loff_t (signed 64-bit), while `sb-\u003es_blocksize` is\nunsigned long.  On 32-bit kernels unsigned long is 32-bit, so the mask\n\n\t~(sb-\u003es_blocksize - 1)\n\nis computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB\nblock size).  In the AND expression with the 64-bit `ctx-\u003epos`, that\nunsigned operand is zero-extended to 64 bits per the usual arithmetic\nconversions, yielding 0x00000000fffff000.  The high 32 bits of\n`ctx-\u003epos` are silently cleared, even though directory size is\nallowed to exceed 4 GiB.\n\nWhen readdir() crosses the 4 GiB boundary on a 32-bit kernel the\nposition is reset back into the first 4 GiB block, making the\nre-validation path re-enumerate already-returned dirents indefinitely.\n\nThis is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken\nfor all non-inline directories, so a directory large enough to cross\n4 GiB reaches it.\n\nThis is the same class of bug that commit 3dce5bb82c97 (\"exfat: Fix\nbitwise operation having different size\") fixed in exfat, and the\nfix mirrors the equivalent ext4 fix in this series.  Cast the operand\nto loff_t so the mask is 64-bit before the AND:\n\n\tctx-\u003epos = (ctx-\u003epos & ~((loff_t)sb-\u003es_blocksize - 1)) | offset;\n\n64-bit kernels are unaffected.","modified":"2026-09-13T06:06:36Z","published":"2026-09-11T20:19:30Z","upstream":["CVE-2026-89490"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89490"}],"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-100220.json"}}],"schema_version":"1.9.0"}