Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-89490— ocfs2: fix readdir position truncation on 32-bit kernels

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，已修复以下漏洞： ocfs2：修复 32 位内核上 readdir 位置截断问题 在 中，目录 cookie 的位置通过以下方式重建： 其中， 的类型是 （带符号的 64 位整数），而 的类型是 。在 32 位内核中， 仅为 32 位，因此掩码： 是作为 32 位无符号值计算的（例如，对于 4 KiB 块大小，值为 ）。在与 64 位的 进行按位与运算时，根据常规算术转换规则，该无符号操作数会被零扩展为 64 位，结果变为 。这导致 的高 32 位被静默清零，尽管目录大小允许超过 4 GiB

AI Predicted 4.1 Difficulty: Moderate

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux ccd979bdbce9fba8412beb3f1de68a9d0171b12c< 1001fb3b69a11eaa0dc7c7428f6edfa48b88997a affected
ccd979bdbce9fba8412beb3f1de68a9d0171b12c< c0c165487a2ea5a37ddcdab4259157b7a527129c affected
ccd979bdbce9fba8412beb3f1de68a9d0171b12c< b53e2b271eeb6040c2a4a78230c570dc41cdcfa4 affected
ccd979bdbce9fba8412beb3f1de68a9d0171b12c< a63308ab426f3a3c7e33b02c150ea59054620261 affected
2.6.16 affected
< 2.6.16 unaffected
6.12.109≤ 6.12.* unaffected
6.18.50≤ 6.18.* unaffected
… +2 more rows
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-89490

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
ocfs2: fix readdir position truncation on 32-bit kernels
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux ccd979bdbce9fba8412beb3f1de68a9d0171b12c ~ 1001fb3b69a11eaa0dc7c7428f6edfa48b88997a -
Linux Linux 2.6.16 -

II. Public POCs for CVE-2026-89490

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-89490

请登录查看更多情报信息。

Other References for CVE-2026-89490 (4)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89491 ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()
CVE-2026-89477 sctp: fix NULL deref on untransmitted RECONF completion
CVE-2026-89478 sctp: drop a chunk if its transport was removed
CVE-2026-89479 sctp: stop processing a packet once its association is deleted
CVE-2026-89480 nvme-tcp: reject a read that transferred too few bytes
CVE-2026-89482 nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89481 nvme-tcp: fix host memory disclosure on R2T for a read command
CVE-2026-89483 nvme: zero the discard fallback page
CVE-2026-89484 lockd: fix NULL dereference on lockowner allocation failure
CVE-2026-89485 lockd: pin next file across nlm_inspect_file lock-drop
CVE-2026-89486 ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
CVE-2026-89487 openvswitch: only skb_tx_error() a packet we are about to drop
CVE-2026-89488 openvswitch: Fix CT limit teardown use-after-free
CVE-2026-89489 openrisc: fix arbitrary kernel memory access via or1k_atomic syscall
CVE-2026-89501 ring-buffer: Hold cpu_buffer::lock when resizing a subbuf
CVE-2026-89498 orangefs: fix double-free of trailer_buf on readdir copy failure
CVE-2026-89499 ring-buffer: Stop remote reader update when page swap fails
CVE-2026-89500 ring-buffer: Make cpu_buffer::free_page a buffer_data_read_page
CVE-2026-89497 orangefs: skip leading spaces before parsing client debug masks
CVE-2026-89502 ring-buffer: Free cpu_buffer::free_page with subbuf_order

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-89490

No comments yet

Leave a comment