CVE-2026-98262
ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY
Description
In the Linux kernel, the following vulnerability has been resolved: ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board. The failure is seen as soon as the ahci driver is probed, and booting with iommu=off does not solve the problem. Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0' for HBAs that do not support 64-bit addressing. For HBAs that do support 64-bit addressing, the registers are read write, with a reset value that is Implementation Specific. When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64. Thus, in this case, we need to explicitly clear the registers to 0.
INFO
Published Date :
Oct. 6, 2026, 9:18 a.m.
Last Modified :
Oct. 6, 2026, 9:18 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel.
- Apply the ahci driver fix.
- Ensure DMA mask is correctly set.
- Clear PxCLBU and PxFBU registers.
References to Advisories, Solutions, and Tools
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information, practical solutions, and valuable tools related to
CVE-2026-98262.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-98262 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-98262
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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CVE-2026-98262 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-98262 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 06, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board. The failure is seen as soon as the ahci driver is probed, and booting with iommu=off does not solve the problem. Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0' for HBAs that do not support 64-bit addressing. For HBAs that do support 64-bit addressing, the registers are read write, with a reset value that is Implementation Specific. When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64. Thus, in this case, we need to explicitly clear the registers to 0. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98262.json">CVE-2026-98262</a> Added Reference https://git.kernel.org/stable/c/0191c9ff23ef1678dbfb5ad253a2dee92feb5d71 Added Reference https://git.kernel.org/stable/c/4719424bb7cb9f20b73986bcb72dd528f0e5c6eb Added Reference https://git.kernel.org/stable/c/7912ad8fb5233bb8cfe21d50df639c7f4854ff9d Added Reference https://git.kernel.org/stable/c/82e47533221d4746947b74d2e79a478c36c6433a Added Reference https://git.kernel.org/stable/c/8f510f68208a1f673d7c7234a687be4671490e9c Added Reference https://git.kernel.org/stable/c/a5a8b4737f68bbac8aa0685af0c8921e6003c22b Added Reference https://git.kernel.org/stable/c/b28a17d4a9bb0aa38b48681c3927b012ba40eabe Added Reference https://git.kernel.org/stable/c/b691a3e244278362e552439d6d3ee5a5d3703488