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Linux KernelOperating system · Linux

CVE-2025-39920

MEDIUM · 5.5 CVSS v3.1 Published 2025-10-01
Fix available
A fix is available. Upgrade to 5.4.299 / 5.10.243 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: pcmcia: Add error handling for add_interval() in do_validate_mem() In the do_validate_mem(), the call to add_interval() does not handle errors. If kmalloc() fails in add_interval(), it could result in a null pointer being inserted into the linked list, leading to illegal memory access when sub_interval() is called next. This patch adds an error handling for the add_interval(). If add_interval() returns an error, the function will return early with the error code.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 2.6.34, < 5.4.299>= 5.5, < 5.10.243>= 5.11, < 5.15.192>= 5.16, < 6.1.151>= 6.2, < 6.6.105>= 6.7, < 6.12.46>= 6.13, < 6.16.6= 6.17
Debian LinuxOperating system
Affected:= 11.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.4.299 / 5.10.243 / 5.15.192 or later
Fixed in 5.4.2995.10.2435.15.192
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel 5.4.299+, 5.10.243+, 5.15.192+, or 6.1.151+ (or latest stable of your branch)

  1. Identify the currently running kernel version using `uname -r`
  2. Determine which kernel branch your current version belongs to (e.g., 5.4.x, 5.10.x, 5.15.x, or 6.1.x)
  3. For kernel 5.4.x: upgrade to version 5.4.299 or later
  4. For kernel 5.5-5.10.x: upgrade to version 5.10.243 or later
  5. For kernel 5.11-5.15.x: upgrade to version 5.15.192 or later
  6. For kernel 5.16-6.1.x: upgrade to version 6.1.151 or later
  7. Alternatively, apply the vendor patch from commit 06b26e3099207c94b3d1be8565aedc6edc4f0a60 to backport the fix
  8. Reboot the system into the new kernel to apply the fix
Caveat Kernel upgrades may introduce compatibility issues with custom modules or older hardware drivers; ensure all proprietary drivers support the target kernel version

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,850. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-39920 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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