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Linux KernelOperating system · Linux

CVE-2026-31589

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-24
Fix available
A fix is available. Upgrade to 6.19.14 / 7.0.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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: mm: call ->free_folio() directly in folio_unmap_invalidate() We can only call filemap_free_folio() if we have a reference to (or hold a lock on) the mapping. Otherwise, we've already removed the folio from the mapping so it no longer pins the mapping and the mapping can be removed, causing a use-after-free when accessing mapping->a_ops. Follow the same pattern as __remove_mapping() and load the free_folio function pointer before dropping the lock on the mapping. That lets us make filemap_free_folio() static as this was the only caller outside filemap.c.

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 · high confidence

Linux kernel memory management use-after-free vulnerability in folio_unmap_invalidate(). The function calls filemap_free_folio() without proper reference to the mapping, allowing the mapping to be removed after the folio is detached, causing a use-after-free when accessing mapping->a_ops. The fix loads the free_folio function pointer before dropping the mapping lock, following the pattern used in __remove_mapping().

MitigationApply the kernel patch that restructures folio_unmap_invalidate() to load the free_folio function pointer before releasing the mapping lock, preventing the race condition that leads to use-after-free of mapping->a_ops.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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:>= 6.14, < 6.19.14>= 7.0, < 7.0.1

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed kernel version
    Run 'uname -r' or 'cat /proc/version' to see the running kernel version
    Affected if The version is >= 6.14 and < 6.19.14, or >= 7.0 and < 7.0.1
  2. Verify folio_unmap_invalidate function exists
    Check if the function folio_unmap_invalidate exists in the kernel image: 'grep -r folio_unmap_invalidate /boot/System.map-$(uname -r)' or check /proc/kallsyms if available
    Affected if The function symbol is present in the kernel, indicating the vulnerable code path exists
  3. Confirm memory mapping usage triggers the vulnerable code
    The vulnerability is in the folio_unmap_invalidate function which handles folio unmapping during invalidation. This code path is exercised when using memory-mapped files or page cache operations.
    Affected if The system uses memory-mapped files (mmap), munmap, or any operations that trigger folio invalidation in the page cache

You are affected if your running kernel version falls within 6.14 to 6.19.13, or 7.0.0, and the system uses memory-mapped file operations that trigger the folio_unmap_invalidate code path.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 6.19.14 / 7.0.1 or later
Fixed in 6.19.147.0.1
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch that restructures folio_unmap_invalidate() to load the free_folio function pointer before releasing the mapping lock, preventing the race condition that leads to use-after-free of mapping->a_ops.

Recommended fix High confidence

Linux Kernel 6.19.14 or 7.0.1 (depending on which major version branch you are on)

  1. 1. Identify the currently running Linux kernel version using 'uname -r' or 'cat /proc/version'
  2. 2. If running kernel >= 6.14 and < 6.19.14, plan to upgrade to kernel version 6.19.14 or later
  3. 3. If running kernel >= 7.0 and < 7.0.1, plan to upgrade to kernel version 7.0.1 or later
  4. 4. For distribution-specific kernels (e.g., Debian, Ubuntu, RHEL), check if a point release update is available that includes the fix commit 615d9bb2ccad42f9e21d837431e401db2e471195
  5. 5. Apply the kernel upgrade through your distribution's standard package management (e.g., 'apt-get dist-upgrade' or 'yum update')
  6. 6. Reboot the system to load the patched kernel
  7. 7. Verify the new kernel version is running with 'uname -r'
Caveat Kernel upgrades may require driver/module compatibility verification; ensure critical hardware drivers are compatible with the target version

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing12.0 h
  • Review / QA6.0 h
26.0 hours of engineering $4,400
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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-2026-31589 in production — separate from our analysis above.

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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
  • No spam, self-promotion, credentials, or personal data