CVE-2026-98262 — ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
≥ c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c and < 0191c9ff23ef1678dbfb5ad253a2dee92feb5d71≥ c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c and < 8f510f68208a1f673d7c7234a687be4671490e9c≥ c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c and < 4719424bb7cb9f20b73986bcb72dd528f0e5c6eb≥ c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c and < a5a8b4737f68bbac8aa0685af0c8921e6003c22b≥ c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c and < b28a17d4a9bb0aa38b48681c3927b012ba40eabe≥ c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c and < b691a3e244278362e552439d6d3ee5a5d3703488≥ c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c and < 7912ad8fb5233bb8cfe21d50df639c7f4854ff9d≥ c7a42156d99bcea7f8173ba7a6034bbaa2ecb77c and < 82e47533221d4746947b74d2e79a478c36c6433a and 1 moreversion 2.6.22 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.18%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Not enough vector or weakness data: use the affected application’s logs as a starting point.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- Affected products added · linux/linux
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
8 on the record
- git.kernel.org/stable/c/4719424bb7cb9f20b73986bcb72dd528f0e5c6eb
- git.kernel.org/stable/c/b28a17d4a9bb0aa38b48681c3927b012ba40eabe
- git.kernel.org/stable/c/82e47533221d4746947b74d2e79a478c36c6433a
- git.kernel.org/stable/c/b691a3e244278362e552439d6d3ee5a5d3703488
- git.kernel.org/stable/c/8f510f68208a1f673d7c7234a687be4671490e9c
- git.kernel.org/stable/c/0191c9ff23ef1678dbfb5ad253a2dee92feb5d71
- git.kernel.org/stable/c/7912ad8fb5233bb8cfe21d50df639c7f4854ff9d
- git.kernel.org/stable/c/a5a8b4737f68bbac8aa0685af0c8921e6003c22b
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 8h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 8h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CVSS score published by NVD, the CNA, CISA or GitHub so far.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-98262 is "ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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