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CVE-2026-89494— ocfs2: validate lengths in dlm_mig_lockres_handler

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存在安全漏洞，该漏洞源于未验证DLM_MIG_LOCKRES消息中的num_locks和lockname_len字段，可能导致越界读取和堆越界写入，进而引发内核崩溃。

CVSS 9.8 · Critical EPSS 0.70% · P52

Possible ATT&CK Techniques 1 AI

T1059.002 · AppleScript

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 6714d8e86bf443f6f7af50f9d432025649f091f5< 4a5798253212093b9ff7d90c6cfbe348bcda1594 affected
6714d8e86bf443f6f7af50f9d432025649f091f5< dce05b17db862f47ff60614017abe639b2e71cad affected
6714d8e86bf443f6f7af50f9d432025649f091f5< 0e999d56917f861f97adb961617b1828c9eb4733 affected
6714d8e86bf443f6f7af50f9d432025649f091f5< 77686fa5bba135252d348e2dacf481fc19f60c41 affected
6714d8e86bf443f6f7af50f9d432025649f091f5< f33041906885f96e190cde54e61ddc69de39e3ee affected
6714d8e86bf443f6f7af50f9d432025649f091f5< 50c4cc9183e11f83427efbf770f54851f4471c02 affected
6714d8e86bf443f6f7af50f9d432025649f091f5< a8facb1670b4a0612183198e758d9539ef628ed9 affected
6714d8e86bf443f6f7af50f9d432025649f091f5< b54e03d9b3697d25f4a0063cf717d459c5e3ad94 affected
… +10 more rows
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I. Basic Information for CVE-2026-89494

Vulnerability Information
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Vulnerability Title
ocfs2: validate lengths in dlm_mig_lockres_handler
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate lengths in dlm_mig_lockres_handler A node receiving a DLM_MIG_LOCKRES message trusts several fields of the peer-supplied dlm_migratable_lockres without validation. num_locks and lockname_len are bounded only on the sending side, and the message is never checked to actually carry num_locks migratable_lock entries. As a result dlm_process_recovery_data() walks mres->ml[0..num_locks) past the kmalloc(data_len) copy of the message (an out-of-bounds read that ends in a BUG_ON panic), and dlm_init_lockres() copies lockname_len bytes into the fixed 32-byte o2dlm_lockname slab object (a heap out-of-bounds write). Both are reachable by any node in the domain. Validate these fields right after dlm_grab(), before anything uses them -- including the not-joined error path, which already prints mres->lockname with the unbounded lockname_len as a %.*s precision. Reject the message unless lockname_len <= DLM_LOCKID_NAME_MAX, num_locks <= DLM_MAX_MIGRATABLE_LOCKS (the bound the sender already asserts), and the payload is large enough to hold the claimed locks. Conforming recovery and migration messages are unaffected.
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存在安全漏洞，该漏洞源于未验证DLM_MIG_LOCKRES消息中的num_locks和lockname_len字段，可能导致越界读取和堆越界写入，进而引发内核崩溃。
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 6714d8e86bf443f6f7af50f9d432025649f091f5 ~ 4a5798253212093b9ff7d90c6cfbe348bcda1594 -
Linux Linux 2.6.16 -

II. Public POCs for CVE-2026-89494

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III. Intelligence Information for CVE-2026-89494

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Patches & Fixes for CVE-2026-89494 (8)

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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