{"id":"CVE-2026-89490","title":"ocfs2: fix readdir position truncation on 32-bit kernels","summary":"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->pos = (ctx->pos & ~(sb->s_…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < c28dc3407937aa8f225942538cd585c9b28ea65a","Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < 94569154ba49f5f85645d2019c8e206213d8404e","Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < 1ae7029823ae4c91664cb32eec7fb8dd5e1a337a","Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < f9dd5cad8d09110ddff2db1fe756aae93c7552ff","Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < 1001fb3b69a11eaa0dc7c7428f6edfa48b88997a","Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < c0c165487a2ea5a37ddcdab4259157b7a527129c","Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < b53e2b271eeb6040c2a4a78230c570dc41cdcfa4","Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < a63308ab426f3a3c7e33b02c150ea59054620261","Linux 2.6.16"],"published":"2026-09-11","updated":"2026-09-14","sourceUpdated":"2026-09-14T12:00:25.670Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89490","references":[{"url":"https://git.kernel.org/stable/c/c28dc3407937aa8f225942538cd585c9b28ea65a"},{"url":"https://git.kernel.org/stable/c/94569154ba49f5f85645d2019c8e206213d8404e"},{"url":"https://git.kernel.org/stable/c/1ae7029823ae4c91664cb32eec7fb8dd5e1a337a"},{"url":"https://git.kernel.org/stable/c/f9dd5cad8d09110ddff2db1fe756aae93c7552ff"},{"url":"https://git.kernel.org/stable/c/1001fb3b69a11eaa0dc7c7428f6edfa48b88997a"},{"url":"https://git.kernel.org/stable/c/c0c165487a2ea5a37ddcdab4259157b7a527129c"},{"url":"https://git.kernel.org/stable/c/b53e2b271eeb6040c2a4a78230c570dc41cdcfa4"},{"url":"https://git.kernel.org/stable/c/a63308ab426f3a3c7e33b02c150ea59054620261"}],"tags":["cve.org"],"epss":0.00176,"epssPercentile":0.07419,"ingestedAt":"2026-09-14T15:23:07.453Z","slug":"CVE-2026-89490","body":"## Overview\n\nIn 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->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset;\n\n`ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is\nunsigned long.  On 32-bit kernels unsigned long is 32-bit, so the mask\n\n\t~(sb->s_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->pos`, that\nunsigned operand is zero-extended to 64 bits per the usual arithmetic\nconversions, yielding 0x00000000fffff000.  The high 32 bits of\n`ctx->pos` 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->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset;\n\n64-bit kernels are unaffected.\n\n## Affected\n\n- `Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < c28dc3407937aa8f225942538cd585c9b28ea65a`\n- `Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < 94569154ba49f5f85645d2019c8e206213d8404e`\n- `Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < 1ae7029823ae4c91664cb32eec7fb8dd5e1a337a`\n- `Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < f9dd5cad8d09110ddff2db1fe756aae93c7552ff`\n- `Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < 1001fb3b69a11eaa0dc7c7428f6edfa48b88997a`\n- `Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < c0c165487a2ea5a37ddcdab4259157b7a527129c`\n- `Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < b53e2b271eeb6040c2a4a78230c570dc41cdcfa4`\n- `Linux >= ccd979bdbce9fba8412beb3f1de68a9d0171b12c < a63308ab426f3a3c7e33b02c150ea59054620261`\n- `Linux 2.6.16`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":183329,"id":"CVE-2026-89490","ts":1789356674669,"field":"cvss","old":null,"new":"5.5"},{"seq":183328,"id":"CVE-2026-89490","ts":1789356674669,"field":"severity","old":"none","new":"medium"},{"seq":147379,"id":"CVE-2026-89490","ts":1789270210672,"field":"cvss","old":null,"new":"5.5"},{"seq":147378,"id":"CVE-2026-89490","ts":1789270210672,"field":"severity","old":"none","new":"medium"},{"seq":109135,"id":"CVE-2026-89490","ts":1789183730446,"field":"cvss","old":null,"new":"5.5"},{"seq":109134,"id":"CVE-2026-89490","ts":1789183730446,"field":"severity","old":"none","new":"medium"}]}