Bug 2540552 (CVE-2026-97441)

Summary: CVE-2026-97441 kernel: ata: ahci: fail probe if BAR too small for claimed ports
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Advanced Host Controller Interface (AHCI) driver. When a storage controller reports more ports than can fit within its allocated Base Address Register (BAR) memory space, the driver attempts to access registers beyond the mapped boundary. A local attacker or malicious hardware device could exploit this condition during device initialization to trigger a kernel panic, resulting in a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-24 17:13:42 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ata: ahci: fail probe if BAR too small for claimed ports

When an AHCI controller is disabled in BIOS, its HOST_CAP register may
contain a bogus value, e.g. 0xFFFFFFFF.

Since CAP.NP (Number of Ports) is a zeroes based 5-bit register field,
a value of 0x1f means 32 ports. If CAP.NP claims more ports than can
physically fit within the mapped BAR region, accessing port registers
beyond the BAR boundary causes a kernel panic.

Add validation in ahci_init_one() to check that the BAR size is
sufficient for the number of ports claimed in CAP.NP. The check
calculates the required MMIO size as:

  required_size = 0x100 (global registers) + max_ports * 0x80

If required_size exceeds the actual BAR size, the probe fails with
-ENODEV, preventing the panic and providing a clear error message.

[cassel: commit log]
Comment 1 Mauro Matteo Cascella 2026-09-29 14:47:51 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97441.mbox