# CVE-2025-38282: kernfs: Relax constraint in draining guard

Status: published. Published: 2025-07-10. Updated: 2026-11-05.

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.)

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ bdb2fd7fc56e197a63c0b0e7e07d25d5e20e7c72; < 2d6a67c2b3b87808a347dc1047b520a9dd177a4f (affected, git); ≥ bdb2fd7fc56e197a63c0b0e7e07d25d5e20e7c72; < 6c81f1c7812c61f187bed1b938f1d2e391d503ab (affected, git); ≥ bdb2fd7fc56e197a63c0b0e7e07d25d5e20e7c72; < 6bfb154f95d5f0ab7ed056f23aba8c1a94cb3927 (affected, git); ≥ bdb2fd7fc56e197a63c0b0e7e07d25d5e20e7c72; < 72275c888f8962b406ee9c6885c79bf68cca5a63 (affected, git); ≥ bdb2fd7fc56e197a63c0b0e7e07d25d5e20e7c72; < 071d8e4c2a3b0999a9b822e2eb8854784a350f8a (affected, git). Source: CNA: Linux
- Linux / Linux: 6.1 (affected); ≥ 0; < 6.1 (unaffected, semver); ≥ 6.1.142; ≤ 6.1.* (unaffected, semver); ≥ 6.6.94; ≤ 6.6.* (unaffected, semver); ≥ 6.12.34; ≤ 6.12.* (unaffected, semver); ≥ 6.15.3; ≤ 6.15.* (unaffected, semver); ≥ 6.16; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.19% as of 2026-11-05; percentile 8.81%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/2d6a67c2b3b87808a347dc1047b520a9dd177a4f (CNA: Linux)

- https://git.kernel.org/stable/c/6c81f1c7812c61f187bed1b938f1d2e391d503ab (CNA: Linux)

- https://git.kernel.org/stable/c/6bfb154f95d5f0ab7ed056f23aba8c1a94cb3927 (CNA: Linux)

- https://git.kernel.org/stable/c/72275c888f8962b406ee9c6885c79bf68cca5a63 (CNA: Linux)

- https://git.kernel.org/stable/c/071d8e4c2a3b0999a9b822e2eb8854784a350f8a (CNA: Linux)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (ADP: CVE)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2025-38282; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-38282; retrieved 2026-11-05; source updated Not reported

Revision: 8f0a1a2ad9ef54591000de4fb01af1abecfa158479e8aecd4b0adeafa0104977

Canonical: https://y2.dev/cve/CVE-2025-38282

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