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CVE-2026-89653— ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode

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，该漏洞源于解码MDSMap时未拒绝超出CEPH_MAX_MDS的export_targets rank，check_new_map()将每个条目作为固定栈位图中的位编号，导致set_bit()越界写入数组末尾，可能造成内存损坏或内核崩溃。

CVSS 9.8 · Critical EPSS 0.51% · P42

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux d517b3983dd3106ca92d6c5d0d09415a4a09481c< 3740c88ca9cb2210a8dbdd55ea4cec119fbe86fe affected
d517b3983dd3106ca92d6c5d0d09415a4a09481c< 8c823bbab3c24e657469a84db96902ba82d4e8bb affected
d517b3983dd3106ca92d6c5d0d09415a4a09481c< c4addccd05bacbef2144b4db14853d0308a218ac affected
d517b3983dd3106ca92d6c5d0d09415a4a09481c< 736adee11af36e407ed902264f8b2fb5cf94b62f affected
d517b3983dd3106ca92d6c5d0d09415a4a09481c< 4d298880f82c42383b36946bafde7ccf4d804c9b affected
d517b3983dd3106ca92d6c5d0d09415a4a09481c< 96c3f5fbb0d5386e7111426f047f98cec4586674 affected
d517b3983dd3106ca92d6c5d0d09415a4a09481c< aedc9053d909508a5f56c3f49f885fc030df4730 affected
5.15 affected
… +8 more rows
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I. Basic Information for CVE-2026-89653

Vulnerability Information
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Vulnerability Title
ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode MDSMap export_targets entries are monitor controlled. check_new_map() uses each entry as a bit number in a fixed stack bitmap, so a rank outside the protocol namespace can make set_bit() write past the end of the array. Reject ranks outside CEPH_MAX_MDS while decoding the map. Do not validate against possible_max_rank here because maps may legitimately reference ranks beyond a temporarily reduced max_mds.
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，该漏洞源于解码MDSMap时未拒绝超出CEPH_MAX_MDS的export_targets rank，check_new_map()将每个条目作为固定栈位图中的位编号，导致set_bit()越界写入数组末尾，可能造成内存损坏或内核崩溃。
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 d517b3983dd3106ca92d6c5d0d09415a4a09481c ~ 3740c88ca9cb2210a8dbdd55ea4cec119fbe86fe -
Linux Linux 5.15 -

II. Public POCs for CVE-2026-89653

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III. Intelligence Information for CVE-2026-89653

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Patches & Fixes for CVE-2026-89653 (7)

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

CVE-2026-89688 9.8 CRITICAL nfsd: drop the stateid, not the stateowner, on seqid_op replay retry
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-2026-89686 9.8 CRITICAL nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke
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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