CVE-2026-80620 - Vulnerability Details

- Revert "PCI/MSI: Unmap MSI-X region on error"

Description

In the Linux kernel, the following vulnerability has been resolved:

Revert "PCI/MSI: Unmap MSI-X region on error"

This reverts commit 1a8d4c6ecb4c81261bcdf13556abd4a958eca202.

Commit 1a8d4c6ecb4c ("PCI/MSI: Unmap MSI-X region on error") added an
iounmap(dev->msix_base) on the error path of msix_capability_init() to
release the MSI-X region when msix_setup_interrupts() fails.

When msix_setup_interrupts() fails, the call chain is:

msix_setup_interrupts()
-> __msix_setup_interrupts()
struct pci_dev *dev __free(free_msi_irqs) = __dev;
...
return ret; // __free cleanup fires on error

The __free(free_msi_irqs) cleanup calls pci_free_msi_irqs(), which
already handles the unmap:

void pci_free_msi_irqs(struct pci_dev *dev)
{
pci_msi_teardown_msi_irqs(dev);
if (dev->msix_base) {
iounmap(dev->msix_base); // already unmapped here
dev->msix_base = NULL; // and set to NULL
}
}

So dev->msix_base is unmapped and set to NULL before
msix_setup_interrupts() returns to msix_capability_init(). The
"goto out_unmap" introduced by commit 1a8d4c6ecb4c ("PCI/MSI: Unmap
MSI-X region on error") then calls iounmap() a second time on a NULL
pointer.

This was reproduced on Intel Emerald Rapids (192 CPUs) while
running tools/testing/selftests/kexec/test_kexec_jump.sh:

WARNING: CPU#44 at iounmap+0x2a/0xe0
RIP: 0010:iounmap+0x2a/0xe0
RDI: 0000000000000000
Call Trace:
msix_capability_init+0x317/0x3f0
__pci_enable_msix_range+0x21d/0x2c0
pci_alloc_irq_vectors_affinity+0xa9/0x130
nvme_setup_io_queues+0x2a8/0x420 [nvme]
nvme_reset_work+0x151/0x340 [nvme]
...

RDI=0 confirms iounmap() is called with NULL.

Restore the original "goto out_disable" and leave the unmap to the
existing __free(free_msi_irqs) cleanup.

Published: 2026-08-28

Score: n/a

EPSS: n/a

KEV: No

Impact:

Action:

Analysis

Impact

In the Linux kernel, a revert commit introduced a double iounmap call on a NULL pointer during the error path of msix_capability_init(). This flaw causes the kernel to crash via a panic whenever msix_setup_interrupts() fails, as the cleanup routines attempt to unmap the MSI‑X region a second time with a NULL address.

Affected Systems

The vulnerability is present in any Linux kernel release that contains the problematic revert, regardless of distribution or hardware. Because the commit is part of the upstream kernel source, every system that has applied this revert is potentially affected; the issue is independent of specific CPU vendor, as it was reproduced on Intel Emerald Rapids.

Risk and Exploitability

The flaw leads to an immediate denial‑of‑service through a kernel panic, but no EPSS data or KEV listing is available and the CVSS score has not been assigned. The attack can be triggered locally by causing msix_setup_interrupts() to fail – for example, through a buggy driver or problematic PCI hardware – which then drives the error path that removes the MSI‑X mapping twice.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`4a7589b615a3db6792d36b874add86cd22188c95`	affected	< 82e120a7dd566c476ba923d30e3fb78e8118a1dd
`5f007c6acaa7d9a543b492c1e48c48a0ea1d7147`	affected	< 6848ca381edff84f87dd1b6973848c271541e813
`76f7abd4ee0188f06465bdd3c053fdc5e8595152`	affected	< 0a2aeb02894b839ecc3ece6dc7e5c3d6c3def16f
`aee8db5f048616990dbdefcc25689ade0a2620ec`	affected	< f79519f636059b007d6abc91652f36dea4f54a20
`1a8d4c6ecb4c81261bcdf13556abd4a958eca202`	affected	< 3691a82be2095abaf3326a1cbf7b25858a1d959c
`1a8d4c6ecb4c81261bcdf13556abd4a958eca202`	affected	< f64e03da0d83cb173743888bff4a7e61476a8fc2
`19bf27b450fcd5309bacd614b12bd7de1ac6535b`	affected	—
`6.1.165`	affected	< 6.1.178
`6.6.128`	affected	< 6.6.145
`6.12.75`	affected	< 6.12.97
`6.18.16`	affected	< 6.18.40
`6.19.6`	affected	< 6.20

Linux

affected

Version	Status	Constraints
`7.0`	affected	—
`0`	unaffected	< 7.0
`6.1.178`	unaffected	≤ 6.1.*
`6.6.145`	unaffected	≤ 6.6.*
`6.12.97`	unaffected	≤ 6.12.*
`6.18.40`	unaffected	≤ 6.18.*
`7.1.5`	unaffected	≤ 7.1.*
`7.2`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[4a7589b615a3db6792d36b874add86cd22188c95,82e120a7dd566c476ba923d30e3fb78e8118a1dd)`	affected	code_commit	—
`[5f007c6acaa7d9a543b492c1e48c48a0ea1d7147,6848ca381edff84f87dd1b6973848c271541e813)`	affected	code_commit	—
`[76f7abd4ee0188f06465bdd3c053fdc5e8595152,0a2aeb02894b839ecc3ece6dc7e5c3d6c3def16f)`	affected	code_commit	—
`[aee8db5f048616990dbdefcc25689ade0a2620ec,f79519f636059b007d6abc91652f36dea4f54a20)`	affected	code_commit	—
`[1a8d4c6ecb4c81261bcdf13556abd4a958eca202,3691a82be2095abaf3326a1cbf7b25858a1d959c)`	affected	code_commit	—
`[1a8d4c6ecb4c81261bcdf13556abd4a958eca202,f64e03da0d83cb173743888bff4a7e61476a8fc2)`	affected	code_commit	—
`19bf27b450fcd5309bacd614b12bd7de1ac6535b`	affected	code_commit	—
`[6.1.165,6.1.178)`	affected	semver	—
`[6.6.128,6.6.145)`	affected	semver	—
`[6.12.75,6.12.97)`	affected	semver	—
`[6.18.16,6.18.40)`	affected	semver	—
`[6.19.6,6.20)`	affected	generic	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`7.0`	affected	generic	—
`[0,7.0)`	unaffected	generic	—
`[0,6.2.0)`	unaffected	semver	—
`[0,6.7.0)`	unaffected	semver	—
`[0,6.13.0)`	unaffected	semver	—
`[0,6.19.0)`	unaffected	semver	—
`[0,7.2.0)`	unaffected	semver	—
`[0,*]`	unaffected	generic	—

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Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Deploy a Linux kernel that has removed the revert bug, such as the latest stable release or the patch that reinstates the original commit (commit 1a8d4c6ecb).
If an update cannot be applied immediately, audit drivers (e.g., NVMe, PCIe devices) that may trigger msix_setup_interrupts() failures and apply any vendor‑provided fixes that prevent the error path from being hit.
As an interim workaround, modify the kernel source (or apply a local patch) to guard the iounmap call against NULL pointers or remove the redundant unmap statement, then rebuild and load the kernel.

Generated by OpenCVE AI on August 28, 2026 at 11:34 UTC.

Tracking

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Advisories

No advisories yet.

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/0a2aeb02894b839ecc3ece6dc7e5c3d6c3def16f
https://git.kernel.org/stable/c/3691a82be2095abaf3326a1cbf7b25858a1d959c
https://git.kernel.org/stable/c/6848ca381edff84f87dd1b6973848c271541e813
https://git.kernel.org/stable/c/82e120a7dd566c476ba923d30e3fb78e8118a1dd
https://git.kernel.org/stable/c/f64e03da0d83cb173743888bff4a7e61476a8fc2
https://git.kernel.org/stable/c/f79519f636059b007d6abc91652f36dea4f54a20

History

Fri, 28 Aug 2026 07:30:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: Revert "PCI/MSI: Unmap MSI-X region on error" This reverts commit 1a8d4c6ecb4c81261bcdf13556abd4a958eca202. Commit 1a8d4c6ecb4c ("PCI/MSI: Unmap MSI-X region on error") added an iounmap(dev->msix_base) on the error path of msix_capability_init() to release the MSI-X region when msix_setup_interrupts() fails. When msix_setup_interrupts() fails, the call chain is: msix_setup_interrupts() -> __msix_setup_interrupts() struct pci_dev dev __free(free_msi_irqs) = __dev; ... return ret; // __free cleanup fires on error The __free(free_msi_irqs) cleanup calls pci_free_msi_irqs(), which already handles the unmap: void pci_free_msi_irqs(struct pci_dev dev) { pci_msi_teardown_msi_irqs(dev); if (dev->msix_base) { iounmap(dev->msix_base); // already unmapped here dev->msix_base = NULL; // and set to NULL } } So dev->msix_base is unmapped and set to NULL before msix_setup_interrupts() returns to msix_capability_init(). The "goto out_unmap" introduced by commit 1a8d4c6ecb4c ("PCI/MSI: Unmap MSI-X region on error") then calls iounmap() a second time on a NULL pointer. This was reproduced on Intel Emerald Rapids (192 CPUs) while running tools/testing/selftests/kexec/test_kexec_jump.sh: WARNING: CPU#44 at iounmap+0x2a/0xe0 RIP: 0010:iounmap+0x2a/0xe0 RDI: 0000000000000000 Call Trace: msix_capability_init+0x317/0x3f0 __pci_enable_msix_range+0x21d/0x2c0 pci_alloc_irq_vectors_affinity+0xa9/0x130 nvme_setup_io_queues+0x2a8/0x420 [nvme] nvme_reset_work+0x151/0x340 [nvme] ... RDI=0 confirms iounmap() is called with NULL. Restore the original "goto out_disable" and leave the unmap to the existing __free(free_msi_irqs) cleanup.
Title		Revert "PCI/MSI: Unmap MSI-X region on error"
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/0a2aeb02894b839ecc3ece6dc7e5c3d6c3def16f https://git.kernel.org/stable/c/3691a82be2095abaf3326a1cbf7b25858a1d959c https://git.kernel.org/stable/c/6848ca381edff84f87dd1b6973848c271541e813 https://git.kernel.org/stable/c/82e120a7dd566c476ba923d30e3fb78e8118a1dd https://git.kernel.org/stable/c/f64e03da0d83cb173743888bff4a7e61476a8fc2 https://git.kernel.org/stable/c/f79519f636059b007d6abc91652f36dea4f54a20

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-08-28T06:48:40.340Z

Updated: 2026-08-28T06:48:40.340Z

Reserved: 2026-08-26T14:34:25.774Z

Link: CVE-2026-80620

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-08-28T08:16:46.083

Modified: 2026-08-28T08:16:46.083

Link: CVE-2026-80620

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-08-28T10:00:06Z

Weaknesses

No weakness.

Impact

Affected Systems

Risk and Exploitability

Tracking

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