CVE-2026-89490: linux

Vulnerability summary

CVE-2026-89490 is a vulnerability in linux with no CVSS score yet. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 6.8% of scored vulnerabilities.

Timeline

1. 11-09-2026
   PublishedVulnerability first disclosed.
2. 19-10-2026
   Last modifiedVulnerability information updated.

Description

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.

No weakness data has been published for this record.