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CVE-2026-98262

Unknown

Last modified

CVE-2026-98262 is a vulnerability of currently unknown severity. 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..

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c, < 0191c9ff23ef1678dbfb5ad253a2dee92feb5d71; >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c, < 8f510f68208a1f673d7c7234a687be4671490e9c; >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c, < 4719424bb7cb9f20b73986bcb72dd528f0e5c6eb; >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c, < a5a8b4737f68bbac8aa0685af0c8921e6003c22b; >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c, < b28a17d4a9bb0aa38b48681c3927b012ba40eabe; >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c, < b691a3e244278362e552439d6d3ee5a5d3703488; >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c, < 7912ad8fb5233bb8cfe21d50df639c7f4854ff9d; >= c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c, < 82e47533221d4746947b74d2e79a478c36c6433a
LinuxLinux2.6.22

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-98262?
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.
How severe is CVE-2026-98262?
Severity scoring for CVE-2026-98262 is pending analysis.
How do I fix CVE-2026-98262?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST