CVE-2025-38282

kernfs: Relax constraint in draining guard

MEDIUM
5.5
CVSS Score
Published: July 10, 2025 at 07:42 AM UTC
Updated: June 17, 2026 at 09:16 AM UTC
2 products affected across 2 vendorsLinux KernelDebian Linux

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%

Description

In the Linux kernel, the following vulnerability has been resolved: kernfs: Relax constraint in draining guard The active reference lifecycle provides the break/unbreak mechanism but the active reference is not truly active after unbreak -- callers don't use it afterwards but it's important for proper pairing of kn->active counting. Assuming this mechanism is in place, the WARN check in kernfs_should_drain_open_files() is too sensitive -- it may transiently catch those (rightful) callers between kernfs_unbreak_active_protection() and kernfs_put_active() as found out by Chen Ridong: kernfs_remove_by_name_ns kernfs_get_active // active=1 __kernfs_remove // active=0x80000002 kernfs_drain ... wait_event //waiting (active == 0x80000001) kernfs_break_active_protection // active = 0x80000001 // continue kernfs_unbreak_active_protection // active = 0x80000002 ... kernfs_should_drain_open_files // warning occurs kernfs_put_active To avoid the false positives (mind panic_on_warn) remove the check altogether. (This is meant as quick fix, I think active reference break/unbreak may be simplified with larger rework.)

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.1 ≤ v < 6.1.1426.1 ≤ v < 6.12.346.1 ≤ v < 6.15.36.1 ≤ v < 6.166.1 ≤ v < 6.6.946.13 ≤ v < 6.15.36.2 ≤ v < 6.6.946.7 ≤ v < 6.12.346.1bdb2fd7fc56e197a63c0b0e7e07d25d5e20e7c72
Vendor states this is fixed in 071d8e4c2a3b0999a9b822e2eb8854784a350f8a (fixed)
Vendor states this is fixed in 2d6a67c2b3b87808a347dc1047b520a9dd177a4f (fixed)
Vendor states this is fixed in 6bfb154f95d5f0ab7ed056f23aba8c1a94cb3927 (fixed)
Vendor states this is fixed in 6c81f1c7812c61f187bed1b938f1d2e391d503ab (fixed)
Vendor states this is fixed in 72275c888f8962b406ee9c6885c79bf68cca5a63 (fixed)
Vendor states this is fixed in 6.1 (unaffected)
Vendor states this is fixed in 6.1.142 (unaffected)
Vendor states this is fixed in 6.12.34 (unaffected)
Vendor states this is fixed in 6.15.3 (unaffected)
Vendor states this is fixed in 6.16 (unaffected)
Vendor states this is fixed in 6.6.94 (unaffected)

References (6)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/071d8e4c2a3b0999a9b822e2eb8854784a350f8a
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/2d6a67c2b3b87808a347dc1047b520a9dd177a4f
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/6bfb154f95d5f0ab7ed056f23aba8c1a94cb3927
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/6c81f1c7812c61f187bed1b938f1d2e391d503ab
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/72275c888f8962b406ee9c6885c79bf68cca5a63
Mailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
NVD-CWE-noinfo

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