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CVE-2025-21664— dm thin: make get_first_thin use rcu-safe list first function

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基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于dm thin模块中get_first_thin函数未正确使用RCU安全的列表操作。这可能导致内存访问错误或系统崩溃。

CVSS 7.8 · High EPSS 0.24% · P14

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux b10ebd34cccae1b431caf1be54919aede2be7cbe< ec037fe8c0d0f6140e3d8a49c7b29cb5582160b8 affected
b10ebd34cccae1b431caf1be54919aede2be7cbe< cd30a3960433ec2db94b3689752fa3c5df44d649 affected
b10ebd34cccae1b431caf1be54919aede2be7cbe< 802666a40c71a23542c43a3f87e3a2d0f4e8fe45 affected
b10ebd34cccae1b431caf1be54919aede2be7cbe< 12771050b6d059eea096993bf2001da9da9fddff affected
b10ebd34cccae1b431caf1be54919aede2be7cbe< 6b305e98de0d225ccebfb225730a9f560d28ecb0 affected
b10ebd34cccae1b431caf1be54919aede2be7cbe< cbd0d5ecfa390ac29c5380200147d09c381b2ac6 affected
b10ebd34cccae1b431caf1be54919aede2be7cbe< 80f130bfad1dab93b95683fc39b87235682b8f72 affected
3.15 affected
… +8 more rows
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I. Basic Information for CVE-2025-21664

Vulnerability Information
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Vulnerability Title
dm thin: make get_first_thin use rcu-safe list first function
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: dm thin: make get_first_thin use rcu-safe list first function The documentation in rculist.h explains the absence of list_empty_rcu() and cautions programmers against relying on a list_empty() -> list_first() sequence in RCU safe code. This is because each of these functions performs its own READ_ONCE() of the list head. This can lead to a situation where the list_empty() sees a valid list entry, but the subsequent list_first() sees a different view of list head state after a modification. In the case of dm-thin, this author had a production box crash from a GP fault in the process_deferred_bios path. This function saw a valid list head in get_first_thin() but when it subsequently dereferenced that and turned it into a thin_c, it got the inside of the struct pool, since the list was now empty and referring to itself. The kernel on which this occurred printed both a warning about a refcount_t being saturated, and a UBSAN error for an out-of-bounds cpuid access in the queued spinlock, prior to the fault itself. When the resulting kdump was examined, it was possible to see another thread patiently waiting in thin_dtr's synchronize_rcu. The thin_dtr call managed to pull the thin_c out of the active thins list (and have it be the last entry in the active_thins list) at just the wrong moment which lead to this crash. Fortunately, the fix here is straight forward. Switch get_first_thin() function to use list_first_or_null_rcu() which performs just a single READ_ONCE() and returns NULL if the list is already empty. This was run against the devicemapper test suite's thin-provisioning suites for delete and suspend and no regressions were observed.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/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基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于dm thin模块中get_first_thin函数未正确使用RCU安全的列表操作。这可能导致内存访问错误或系统崩溃。
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 b10ebd34cccae1b431caf1be54919aede2be7cbe ~ ec037fe8c0d0f6140e3d8a49c7b29cb5582160b8 -
Linux Linux 3.15 -

II. Public POCs for CVE-2025-21664

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III. Intelligence Information for CVE-2025-21664

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Patches & Fixes for CVE-2025-21664 (7)

Same Patch Batch · Linux · 2025-01-21 · 25 CVEs total

CVE-2025-21663 10.0 CRITICAL net: stmmac: dwmac-tegra: Read iommu stream id from device tree
CVE-2024-57932 9.8 CRITICAL gve: guard XDP xmit NDO on existence of xdp queues
CVE-2024-57936 9.8 CRITICAL RDMA/bnxt_re: Fix max SGEs for the Work Request
CVE-2025-21659 8.1 HIGH netdev: prevent accessing NAPI instances from another namespace
CVE-2025-21661 7.8 HIGH gpio: virtuser: fix missing lookup table cleanups
CVE-2024-57945 7.8 HIGH riscv: mm: Fix the out of bound issue of vmemmap address
CVE-2024-57943 exfat: fix the new buffer was not zeroed before writing
CVE-2024-57946 virtio-blk: don't keep queue frozen during system suspend
CVE-2025-21662 net/mlx5: Fix variable not being completed when function returns
CVE-2025-21660 ksmbd: fix unexpectedly changed path in ksmbd_vfs_kern_path_locked
CVE-2025-21658 btrfs: avoid NULL pointer dereference if no valid extent tree
CVE-2025-21657 sched_ext: Replace rq_lock() to raw_spin_rq_lock() in scx_ops_bypass()
CVE-2025-21656 hwmon: (drivetemp) Fix driver producing garbage data when SCSI errors occur
CVE-2024-57944 iio: adc: ti-ads1298: Add NULL check in ads1298_init
CVE-2024-57930 tracing: Have process_string() also allow arrays
CVE-2024-57942 netfs: Fix ceph copy to cache on write-begin
CVE-2024-57941 netfs: Fix the (non-)cancellation of copy when cache is temporarily disabled
CVE-2024-57940 exfat: fix the infinite loop in exfat_readdir()
CVE-2024-57939 riscv: Fix sleeping in invalid context in die()
CVE-2024-57938 net/sctp: Prevent autoclose integer overflow in sctp_association_init()

Showing top 20 of 25 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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