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CVE-2026-64239— mm/damon/sysfs-schemes: delete tried region in regions_rmdirs()

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基金会开源的一款操作系统内核。 Linux kernel 6.2版本存在安全漏洞，该漏洞源于DAMON sysfs中regions_rmdirs()函数在删除尝试区域时，由于kobj对象释放回调延迟导致链表可能包含已释放的对象，从而可能造成释放后重用。

AI Predicted 5.5 Difficulty: Hard EPSS 0.12% · P2

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux 9277d0367ba18ef4bb98bafb1209e715844cdf7e< c0e37017a452addec873865c94cf7a665663a9b2 affected
9277d0367ba18ef4bb98bafb1209e715844cdf7e< a5fa42214de55e43d165144727ce9facb9fc6b08 affected
9277d0367ba18ef4bb98bafb1209e715844cdf7e< 0ba6c05156d9ff9fc6ca22b7690e2eec9eca66f7 affected
9277d0367ba18ef4bb98bafb1209e715844cdf7e< 2c33177023c92e76806c535ddbffaa3d3fc37777 affected
9277d0367ba18ef4bb98bafb1209e715844cdf7e< 441f92f7d386b85bad16de49db95a307cba048a2 affected
6.2 affected
< 6.2 unaffected
6.6.143≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-64239

Vulnerability Information
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Vulnerability Title
mm/damon/sysfs-schemes: delete tried region in regions_rmdirs()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-schemes: delete tried region in regions_rmdirs() DAMON sysfs maintains the DAMOS tried region directory objects via a linked list. When the user requests refresh of the directories, DAMON sysfs removes all the region directories first, and then generate updated regions directory on the empty space. The removal function (damon_sysfs_scheme_regions_rm_dirs()) only puts the kobj objects. Deletion of the container region object from the linked list is done inside the kobj release callback function. If somehow the callback invocation is delayed, the list will contain regions list that gonna be freed. If the updated region directories creation is started in this situation, the list can be corrupted and use-after-free can happen. Because the kobj objects are managed by only DAMON sysfs, the issue cannot happen in normal situation. But, such delays can be made on kernels that built with CONFIG_DEBUG_KOBJECT_RELEASE. On the kernel, the issue can indeed be reproduced like below. # damo start --damos_action stat # cd /sys/kernel/mm/damon/admin/kdamonds/0/ # for i in {1..10}; do echo update_schemes_tried_regions > state; done # dmesg | grep underflow [ 89.296152] refcount_t: underflow; use-after-free. Fix the issue by removing the region object from the list when decrementing the reference count. Also update damos_sysfs_populate_region_dir() to add the region object to the list only after the kobject_init_and_add() is success, so that fail of kobject_init_and_add() is not leaving the deallocated object on the list. The issue was discovered [1] by Sashiko.
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基金会开源的一款操作系统内核。 Linux kernel 6.2版本存在安全漏洞，该漏洞源于DAMON sysfs中regions_rmdirs()函数在删除尝试区域时，由于kobj对象释放回调延迟导致链表可能包含已释放的对象，从而可能造成释放后重用。
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 9277d0367ba18ef4bb98bafb1209e715844cdf7e ~ c0e37017a452addec873865c94cf7a665663a9b2 -
Linux Linux 6.2 -

II. Public POCs for CVE-2026-64239

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III. Intelligence Information for CVE-2026-64239

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Patches & Fixes for CVE-2026-64239 (5)

Same Patch Batch · Linux · 2026-07-24 · 48 CVEs total

CVE-2026-64216 9.8 CRITICAL netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()
CVE-2026-64232 9.8 CRITICAL block: recompute nr_integrity_segments in blk_insert_cloned_request
CVE-2026-64255 8.8 HIGH wifi: iwlwifi: mld: validate sta_mask before ffs() in BA session handlers
CVE-2026-64247 8.4 HIGH KVM: x86: hyper-v: Bound the bank index when querying sparse banks
CVE-2026-64223 8.1 HIGH wifi: mac80211: consume only present negotiated TTLM maps
CVE-2026-64235 8.1 HIGH x86/ftrace: Relocate %rip-relative percpu refs in dynamic trampolines
CVE-2026-64218 7.8 HIGH batman-adv: bla: fix report_work leak on backbone_gw purge
CVE-2026-64226 7.8 HIGH sched_ext: Avoid UAF in scx_root_enable_workfn() init failure path
CVE-2026-64251 7.8 HIGH pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next()
CVE-2026-64221 7.8 HIGH spi: ti-qspi: fix use-after-free after DMA setup failure
CVE-2026-64217 7.8 HIGH netfs: Fix overrun check in netfs_extract_user_iter()
CVE-2026-64208 7.5 HIGH crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks
CVE-2026-64210 7.5 HIGH net/mlx5e: xsk: Fix unlocked writing to ICOSQ
CVE-2026-64243 7.1 HIGH ASoC: codecs: simple-mux: Fix enum control bounds check
CVE-2026-64219 7.0 HIGH drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_as
CVE-2026-64222 7.0 HIGH octeontx2-pf: avoid double free of pool->stack on AQ init failure
CVE-2026-64211 srcu: Don't queue workqueue handlers to never-online CPUs
CVE-2026-64212 wifi: iwlwifi: mld: don't dereference a pointer before NULL checking it
CVE-2026-64209 phy: qcom: qmp-usbc: Fix out-of-bounds array access in dp swing config
CVE-2026-64227 ACPI: driver: Check ACPI_COMPANION() against NULL during probe

Showing top 20 of 48 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-64239

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