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Linux KernelOperating system · Linux

CVE-2026-53067

HIGH · 7.8 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 6.18.33 / 7.0.10 or later.
See remediation →
80/100
Remediation priority · High
Zero-click 8 weeks old

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: PCI: endpoint: pci-ep-msi: Fix error unwind and prevent double alloc pci_epf_alloc_doorbell() stores the allocated doorbell message array in epf->db_msg/epf->num_db before requesting MSI vectors. If MSI allocation fails, the array is freed but the EPF state may still point to freed memory. Clear epf->db_msg and epf->num_db on the MSI allocation failure path so that later cleanup cannot double-free the array and callers can retry allocation. Also return -EBUSY when doorbells have already been allocated to prevent leaking or overwriting an existing allocation.

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

In the Linux kernel PCI endpoint MSI code, pci_epf_alloc_doorbell() stores an allocated doorbell message array before requesting MSI vectors. If MSI allocation fails, the array is freed but the EPF state still points to freed memory, creating a double-free/use-after-free vulnerability. Additionally, no check prevents re-allocation of already-allocated doorbells, potentially causing memory leaks or overwriting.

MitigationApply the kernel patch that clears epf->db_msg and epf->num_db on MSI allocation failure and returns -EBUSY when doorbells are already allocated. Update to a kernel version containing this fix.

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:>= 6.17, < 6.18.33>= 6.19, < 7.0.10

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 kernel version
    Run 'uname -r' to get the running kernel version
    Affected if Kernel version is 6.17.x, 6.18.x through 6.18.32, 6.19.x, or 7.0.x through 7.0.9 (falls within >= 6.17, < 6.18.33 or >= 6.19, < 7.0.10)
  2. Verify PCI endpoint support is enabled
    Check kernel config with 'grep -i CONFIG_PCI_ENDPOINT /boot/config-$(uname -r)' or check /sys/module/pci_epf* existence
    Affected if CONFIG_PCI_ENDPOINT=y or CONFIG_PCI_ENDPOINT=m (module loaded), meaning the PCI endpoint framework is active
  3. Check for PCI endpoint devices in use
    Examine /sys/bus/pci-epf/devices/ or run 'ls /sys/bus/pci-epf/devices/' to list registered endpoint functions
    Affected if Any PCI endpoint function devices are registered, as the vulnerable code path (pci_epf_alloc_doorbell) executes when doorbell allocation is requested
  4. Identify endpoint function drivers
    Run 'lsmod | grep -i pci' and check 'lspci -v' output for 'Endpoint' in device class, or check /sys/class/pci_epf/
    Affected if PCI endpoint function drivers are loaded or bound to devices, triggering the vulnerable code path

You are affected if running an affected kernel version (6.17 to 6.18.32 or 6.19 to 7.0.9) AND the PCI endpoint framework (CONFIG_PCI_ENDPOINT) is enabled with endpoint devices or drivers in use that call pci_epf_alloc_doorbell().

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 6.18.33 / 7.0.10 or later
Fixed in 6.18.337.0.10
Interim mitigation

Apply the kernel patch that clears epf->db_msg and epf->num_db on MSI allocation failure and returns -EBUSY when doorbells are already allocated. Update to a kernel version containing this fix.

Recommended fix High confidence

Linux Kernel 6.18.33 or 7.0.10 (whichever branch applies)

  1. Identify the currently running kernel version using `uname -r`
  2. If running kernel >= 6.17 and < 6.18.33: upgrade to kernel version 6.18.33 or later within the 6.18.y stable branch
  3. If running kernel >= 6.19 and < 7.0.10: upgrade to kernel version 7.0.10 or later within the 7.0.y stable branch
  4. Verify the fix is applied by checking that the pci-ep-msi code properly clears epf->db_msg and epf->num_db on failure and returns -EBUSY for duplicate allocations
  5. Reboot into the new kernel and confirm PCI endpoint functionality works correctly
Caveat Kernel upgrades may require matching kernel modules and may introduce compatibility changes with userspace tools; ensure critical PCI endpoint userland tools are compatible with the target kernel version

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
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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-2026-53067 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
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