CVE-2026-53283 | iommu/amd: Bounds-check devid in __rlookup_amd_iommu()

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.

Published: 2026-06-26 Last update: 2026-07-07 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-53283 is rated Low Risk (22.7/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.12%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-53283

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-08 0.17% 0.12% -0.05%
2 2026-06-27 — 0.17% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-53283

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2026-53283

GitHub Security Advisory for CVE-2026-53283

GHSA-gv9j-3945-3x3r · Severity: medium — In the Linux kernel, the following vulnerability has been resolved: iommu/amd: Bounds-check...

OS Trackers for CVE-2026-53283

vendor priority summary link
debian unimportant CVE-2026-53283 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-53283
suse — — https://www.suse.com/security/cve/CVE-2026-53283/
ubuntu medium CVE-2026-53283 medium priority: Ubuntu including 162 source packages (linux, linux-allwinner-5.19, …), 1458 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1051, ignored 172, not-affected 112, released 88, needed 24, pending 11. https://ubuntu.com/security/CVE-2026-53283

Affected software / configurations for CVE-2026-53283

Vendor Product Version Raw CPE
linux linux_kernel >= 6.16, < 6.18.33 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.19, < 7.0.10 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*

References for CVE-2026-53283

cvelogic Threat Intelligence