CVE-2026-43486 | arm64: contpte: fix set_access_flags() no-op check for SMMU/ATS faults

In the Linux kernel, the following vulnerability has been resolved: arm64: contpte: fix set_access_flags() no-op check for SMMU/ATS faults contpte_ptep_set_access_flags() compared the gathered ptep_get() value against the requested entry to detect no-ops. ptep_get() ORs AF/dirty from all sub-PTEs in the CONT block, so a dirty sibling can make the target appear already-dirty. When the gathered value matches entry, the function returns 0 even though the target sub-PTE still has PTE_RDONLY set in hardware. For a CPU with FEAT_HAFDBS this gathered view is fine, since hardware may set AF/dirty on any sub-PTE and CPU TLB behavior is effectively gathered across the CONT range. But page-table walkers that evaluate each descriptor individually (e.g. a CPU without DBM support, or an SMMU without HTTU, or with HA/HD disabled in CD.TCR) can keep faulting on the unchanged target sub-PTE, causing an infinite fault loop. Gathering can therefore cause false no-ops when only a sibling has been updated: - write faults: target still has PTE_RDONLY (needs PTE_RDONLY cleared) - read faults: target still lacks PTE_AF Fix by checking each sub-PTE against the requested AF/dirty/write state (the same bits consumed by __ptep_set_access_flags()), using raw per-PTE values rather than the gathered ptep_get() view, before returning no-op. Keep using the raw target PTE for the write-bit unfold decision. Per Arm ARM (DDI 0487) D8.7.1 ("The Contiguous bit"), any sub-PTE in a CONT range may become the effective cached translation and software must maintain consistent attributes across the range.

Published: 2026-05-13 Last update: 2026-05-13 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2026-43486 is rated Low Risk (5.3/100): low exploitation likelihood (EPSS 0.16%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-43486

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.16% +0.14%
2 2026-05-14 0.02%

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-43486

CVSS metrics for this CVE.

No CVSS data in dataset for this CVE.

Weakness enumeration for CVE-2026-43486

GitHub Security Advisory for CVE-2026-43486

GHSA-9h93-8p35-79jq · Severity: unknown — In the Linux kernel, the following vulnerability has been resolved: arm64: contpte: fix...

OS Trackers for CVE-2026-43486

vendor priority summary link
debian unimportant CVE-2026-43486 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-43486
redhat medium https://access.redhat.com/security/cve/CVE-2026-43486
suse medium CVE-2026-43486 severity moderate: SUSE including 20 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 178 product×package rows across 35 product lines (SUSE Linux Enterprise High Availability Extension 15 SP7, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, … (35 product lines)): Known Not Affected 178. https://www.suse.com/security/cve/CVE-2026-43486/
ubuntu medium CVE-2026-43486 medium priority: Ubuntu including 161 source packages (linux, linux-allwinner-5.19, …), 1449 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1048, ignored 169, not-affected 114, released 86, needed 26, needs-triage 5, pending 1. https://ubuntu.com/security/CVE-2026-43486

Affected software / configurations for CVE-2026-43486

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-43486

cvelogic Threat Intelligence