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CVE-2026-89757— mm/mglru: fix and remove redundant unevictable folio handling

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mm/mglru的sort_folio()对不可驱逐folio处理不当，未正确设置mlock_count且LRU标志操作顺序错误，可能导致计数错误和意外行为。

AI Predicted 5.5 Difficulty: Hard EPSS 0.21% · P10

Possible ATT&CK Techniques 1 AI

T1565 · Data Manipulation

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux ac35a490237446b71e3b4b782b1596967edd0aa8< 54a58d6656dd403b686b247f0bad8507cbfb45df affected
ac35a490237446b71e3b4b782b1596967edd0aa8< 15d3a2a71c8bf7333d019d249ee33669e69e4275 affected
ac35a490237446b71e3b4b782b1596967edd0aa8< f7e698e326b239a91ea15844817551921209e826 affected
6.1 affected
< 6.1 unaffected
6.18.51≤ 6.18.* unaffected
7.2.4≤ 7.2.* unaffected
7.3-rc1≤ * unaffected
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I. Basic Information for CVE-2026-89757

Vulnerability Information
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Vulnerability Title
mm/mglru: fix and remove redundant unevictable folio handling
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: mm/mglru: fix and remove redundant unevictable folio handling sort_folio() has a shortcut for moving folios that are no longer evictable but are still sitting on a generation list. However, this shortcut is buggy. It does not follow the PG_lru usage convention, and it has a more serious issue. Unevictable folios are not threaded on lists[LRU_UNEVICTABLE], so that folio->lru can be reused to hold folio->mlock_count (see the comment in lruvec_init()). Hence lruvec_add_folio() skips the list_add() for them, and every other place that turns a folio unevictable initialises mlock_count explicitly: lru_add() sets it to 0, __mlock_folio() and __mlock_new_folio() set it to !!folio_test_mlocked(folio). sort_folio() sets nothing, and the lru_gen_del_folio() right above it may have already poisoned folio->lru via list_del(), so mlock_count ends up aliasing LIST_POISON2, which reads as 0x122, i.e. 290. The result is user visible. On munlock, __munlock_folio() decrements that bogus count, finds it still non-zero and bails out before clearing PG_mlocked, so the folio remains unevictable and the Mlocked accounting stays inflated until the folio is freed. The shortcut also touches the LRU flags in the wrong order. It calls lru_gen_del_folio() while PG_lru is still set, so a concurrent folio_test_clear_lru() (e.g. compaction, folio_isolate_lru()) can succeed on a folio that has already been taken off the generation list, which may lead to unexpected behavior. So fix it by isolating them as common folios and letting the generic shrink path cull them. This matches the classical LRU behavior, and there should be no visible effect on the generic eviction or isolation behavior. There is no performance concern either, such a folio goes through this once, and then it is off the generation lists for good.
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
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mm/mglru的sort_folio()对不可驱逐folio处理不当，未正确设置mlock_count且LRU标志操作顺序错误，可能导致计数错误和意外行为。
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 ac35a490237446b71e3b4b782b1596967edd0aa8 ~ 54a58d6656dd403b686b247f0bad8507cbfb45df -
Linux Linux 6.1 -

II. Public POCs for CVE-2026-89757

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III. Intelligence Information for CVE-2026-89757

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Patches & Fixes for CVE-2026-89757 (3)

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

CVE-2026-89669 9.8 CRITICAL nfsd: initialize copy-notify stateid before publishing it
CVE-2026-89536 9.8 CRITICAL SUNRPC: wait for in-flight client TLS handshake callback
CVE-2026-89533 9.8 CRITICAL svcrdma: Fix offset arithmetic in read_chunk_range
CVE-2026-81002 9.8 CRITICAL xdp: fix zero-copy frame layout
CVE-2026-89643 9.8 CRITICAL audit: avoid dropping live tree ref on fsnotify rule autoremove
CVE-2026-89526 9.8 CRITICAL svcrdma: Validate Read chunk positions before reconstruction
CVE-2026-89652 9.8 CRITICAL ceph: bound copied dentry name length in NFS export get_name
CVE-2026-89651 9.8 CRITICAL ceph: bound MDSCapAuth path and fs_name decode in handle_session()
CVE-2026-89653 9.8 CRITICAL ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode
CVE-2026-89654 9.8 CRITICAL ceph: fix UAF in check_new_map() on session freed during unlock
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-2026-89712 9.8 CRITICAL NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock
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-2026-89708 9.8 CRITICAL nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown
CVE-2026-89662 9.8 CRITICAL NFSD: Prevent lock owner use-after-free during client teardown
CVE-2026-89689 9.8 CRITICAL nfsd: don't free session slots that are still in use
CVE-2026-89686 9.8 CRITICAL nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke

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-2026-89757

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