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Linux KernelOperating system · Linux

CVE-2026-53283

MEDIUM · 5.5 CVSS v3.1 Published 2026-06-26
Fix available
A fix is available. Upgrade to 6.18.33 / 7.0.10 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available 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: iommu/amd: Bounds-check devid in __rlookup_amd_iommu() iommu_device_register() walks every device on the PCI bus via bus_for_each_dev() and calls amd_iommu_probe_device() for each. The inlined check_device() path computes the device's sbdf, calls rlookup_amd_iommu() to find the owning IOMMU, and only afterwards verifies devid <= pci_seg->last_bdf. __rlookup_amd_iommu() indexes rlookup_table[devid] with no bounds check of its own, so for a PCI device whose BDF is not described by the IVRS, the lookup reads past the end of the allocation before the caller's bounds check can run. This was harmless before commit e874c666b15b ("iommu/amd: Change rlookup, irq_lookup, and alias to use kvalloc()"): the table was a zeroed page-order allocation, so the over-read returned NULL and the caller's NULL check skipped the device. After that commit the table is a tight kvcalloc() and the over-read returns adjacent slab contents, which check_device() then dereferences as a struct amd_iommu *, causing a boot-time GPF. Seen on Google Compute Engine ct6e VMs, where the virtualized IVRS describes only the four TPU endpoints 00:04.0-07.0; the gVNIC at 00:08.0 (devid 0x40) indexes 56 bytes past the 456-byte allocation, into the adjacent kmalloc-512 slab object: pci 0000:00:04.0: Adding to iommu group 0 pci 0000:00:05.0: Adding to iommu group 1 pci 0000:00:06.0: Adding to iommu group 2 pci 0000:00:07.0: Adding to iommu group 3 Oops: general protection fault, probably for non-canonical address 0x3a64695f78746382: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.18.22 #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/06/2025 RIP: 0010:amd_iommu_probe_device+0x54/0x3a0 Call Trace: __iommu_probe_device+0x107/0x520 probe_iommu_group+0x29/0x50 bus_for_each_dev+0x7e/0xe0 iommu_device_register+0xc9/0x240 iommu_go_to_state+0x9c0/0x1c60 amd_iommu_init+0x14/0x40 pci_iommu_init+0x16/0x60 do_one_initcall+0x47/0x2f0 Guard the array access in __rlookup_amd_iommu(). With the fix applied on 6.18.22, the gVNIC at 00:08.0 is skipped cleanly and the VM boots.

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:>= 6.16, < 6.18.33>= 6.19, < 7.0.10= 7.1

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
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 6.18.33 / 7.0.10 or later
Fixed in 6.18.337.0.10
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel >= 6.18.33 (for 6.16-6.18.x systems), >= 7.0.10 (for 6.19-7.0.x systems), or >= 7.2 (for 7.1 systems)

  1. Identify the current running kernel version using `uname -r`
  2. Check if the system is running an affected version: >= 6.16 and < 6.18.33, or >= 6.19 and < 7.0.10, or exactly 7.1
  3. Schedule a maintenance window for kernel upgrade (requires system reboot)
  4. Upgrade the Linux kernel to version 6.18.33 or later for the 6.16-6.18.x branch
  5. Upgrade to version 7.0.10 or later for the 6.19-7.0.x branch
  6. Upgrade to version 7.2 or later if currently on 7.1
  7. After reboot, verify the fix is applied by checking `cat /proc/version` matches the upgraded version
  8. Confirm the vulnerability is resolved by ensuring the kernel boots without the GPF error described in the CVE
Caveat Kernel upgrades may require updating out-of-tree drivers or kernel modules; ensure compatibility before upgrading production systems

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-2026-53283 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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