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CVE-2026-89492— ocfs2: validate directory-index entry counts when reading metadata

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.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 2.6.30版本存在安全漏洞，该漏洞源于ocfs2在读取元数据时未验证目录索引条目计数与块容量，导致ocfs2_dx_dir_search()遍历时无边界检查，特制磁盘镜像可触发slab越界读取，可能在挂载后通过路径查找、stat()或open()触发。

CVSS 9.8 · Critical EPSS 0.63% · P49

Possible ATT&CK Techniques 1 AI

T1004.001

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 9b7895efac906d66d19856194e1ba61f37e231a4< 5e661f55ca8568471fce558effe81cca112f5cb2 affected
9b7895efac906d66d19856194e1ba61f37e231a4< fcfcba8fe17dbf2c8805690b8cc25e32d81249a4 affected
9b7895efac906d66d19856194e1ba61f37e231a4< b8a5c0c32df2c5b685ceef76ac77e37c7e1dc3ed affected
9b7895efac906d66d19856194e1ba61f37e231a4< bc70726ddad53c7e9a9a85915bf2415b0d4f42f9 affected
2.6.30 affected
< 2.6.30 unaffected
6.12.111≤ 6.12.* unaffected
6.18.51≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-89492

Vulnerability Information
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Vulnerability Title
ocfs2: validate directory-index entry counts when reading metadata
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate directory-index entry counts when reading metadata ocfs2_validate_dx_leaf() and ocfs2_validate_dx_root() check the ECC and signature of an indexed-directory block before it reaches higher-level callers, but neither validator bounds the ocfs2_dx_entry_list counts against the capacity of the block that holds them. ocfs2_dx_dir_search() then walks for (i = 0; i < le16_to_cpu(entry_list->de_num_used); i++) dx_entry = &entry_list->de_entries[i]; over de_num_used entries with no bounds check. entry_list is either dx_leaf->dl_list (from ocfs2_read_dx_leaf) or, for an inline root, dx_root->dr_entries. A crafted on-disk image can set de_num_used (and de_count, which is the __counted_by_le() bound of de_entries) to 0xffff and make the walk read far past the end of the 4KB metadata block, giving a slab out-of-bounds read reachable from any path lookup, stat() or open() on an indexed directory once the image is mounted. Commit 775c17386a6f ("ocfs2: validate dx_root extent list fields during block read") already bounds dr_list for the non-inline dx_root, but left the inline dr_entries path and the dx_leaf dl_list unchecked. Add the same read-time validation for both entry lists: de_count must equal the capacity of the block (ocfs2_dx_entries_per_leaf()/per_root()) and de_num_used must not exceed de_count, rejecting corrupted metadata with -EFSCORRUPTED before ocfs2_dx_dir_search() can walk an out-of-range entry array. de_count is always written as exactly the block capacity when a leaf or inline root is formatted, so the equality check does not reject any valid image. Found by 0sec automated security-research tooling (https://0sec.ai).
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 2.6.30版本存在安全漏洞，该漏洞源于ocfs2在读取元数据时未验证目录索引条目计数与块容量，导致ocfs2_dx_dir_search()遍历时无边界检查，特制磁盘镜像可触发slab越界读取，可能在挂载后通过路径查找、stat()或open()触发。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 9b7895efac906d66d19856194e1ba61f37e231a4 ~ 5e661f55ca8568471fce558effe81cca112f5cb2 -
Linux Linux 2.6.30 -

II. Public POCs for CVE-2026-89492

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III. Intelligence Information for CVE-2026-89492

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Patches & Fixes for CVE-2026-89492 (3)

Other References for CVE-2026-89492 (1)

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

CVE-2026-89686 9.8 CRITICAL nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke
CVE-2026-89656 9.8 CRITICAL libceph: reject buckets with mismatched CRUSH ids
CVE-2026-89655 9.8 CRITICAL ceph: fix UAF in __kick_flushing_caps() on cf entry freed during unlock
CVE-2026-89658 9.8 CRITICAL NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup
CVE-2026-89660 9.8 CRITICAL NFSD: Prevent client use-after-free during admin state revocation
CVE-2026-89659 9.8 CRITICAL NFSD: Prevent client use-after-free during delegation revoke
CVE-2026-89662 9.8 CRITICAL NFSD: Prevent lock owner use-after-free during client teardown
CVE-2026-89669 9.8 CRITICAL nfsd: initialize copy-notify stateid before publishing it
CVE-2026-89674 9.8 CRITICAL nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
CVE-2026-89675 9.8 CRITICAL nfsd: fix UAF in async copy cancel and shutdown
CVE-2026-89676 9.8 CRITICAL nfsd: fix stale s2s_cp_stateids IDR entry for async COPY
CVE-2026-89677 9.8 CRITICAL nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
CVE-2026-89681 9.8 CRITICAL nfsd: fix layout fence worker double-reference race
CVE-2026-89703 9.8 CRITICAL nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations
CVE-2026-89479 9.8 CRITICAL sctp: stop processing a packet once its association is deleted
CVE-2026-89478 9.8 CRITICAL sctp: drop a chunk if its transport was removed
CVE-2026-89702 9.8 CRITICAL nfsd: size fh_verify server sockaddr slot by xpt_locallen
CVE-2026-89482 9.8 CRITICAL nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89708 9.8 CRITICAL nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown
CVE-2026-89712 9.8 CRITICAL NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock

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

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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