---
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: 0.07434
ingestedAt: '2026-09-14T15:23:07.453Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: fix readdir position truncation on 32-bit kernels

In ocfs2_dir_foreach_blk_el(), the directory cookie position is
rebuilt with

	ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1)) | offset;

`ctx->pos` is loff_t (signed 64-bit), while `sb->s_blocksize` is
unsigned long.  On 32-bit kernels unsigned long is 32-bit, so the mask

	~(sb->s_blocksize - 1)

is computed as a 32-bit unsigned value (e.g. 0xfffff000 for a 4 KiB
block size).  In the AND expression with the 64-bit `ctx->pos`, that
unsigned operand is zero-extended to 64 bits per the usual arithmetic
conversions, yielding 0x00000000fffff000.  The high 32 bits of
`ctx->pos` are silently cleared, even though directory size is
allowed to exceed 4 GiB.

When readdir() crosses the 4 GiB boundary on a 32-bit kernel the
position is reset back into the first 4 GiB block, making the
re-validation path re-enumerate already-returned dirents indefinitely.

This is ocfs2_dir_foreach_blk_el(), the extent-list readdir path taken
for all non-inline directories, so a directory large enough to cross
4 GiB reaches it.

This is the same class of bug that commit 3dce5bb82c97 ("exfat: Fix
bitwise operation having different size") fixed in exfat, and the
fix mirrors the equivalent ext4 fix in this series.  Cast the operand
to loff_t so the mask is 64-bit before the AND:

	ctx->pos = (ctx->pos & ~((loff_t)sb->s_blocksize - 1)) | offset;

64-bit kernels are unaffected.

## 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`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.