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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.11% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0, 09d620555e59768776090073a2c59d2bc8506eb3, 6f92a7a8b48a523f910ef25dd83808710724f59b.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0, 09d620555e59768776090073a2c59d2bc8506eb3, 6f92a7a8b48a523f910ef25dd83808710724f59b or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 13, 2026
Updated
Jun 26, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel6.9 and later · before 6.12.78
  • linux linux kernel6.13 and later · before 6.18.19
  • linux linux kernel6.19 and later · before 6.19.9
  • linux linux kernel7.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.9affected
    • 4602e5757bcceb231c3a13c36c373ad4a750eddb and later · before 05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0affected · git
    • 4602e5757bcceb231c3a13c36c373ad4a750eddb and later · before 6f92a7a8b48a523f910ef25dd83808710724f59baffected · git
    • 4602e5757bcceb231c3a13c36c373ad4a750eddb and later · before 09d620555e59768776090073a2c59d2bc8506eb3affected · git
    • 4602e5757bcceb231c3a13c36c373ad4a750eddb and later · before 97c5550b763171dbef61e6239cab372b9f9cd4a2affected · git
    • before 6.9not affected · semver
    • 6.12.78 and later · up to and including 6.12.*not affected · semver
    • 6.18.19 and later · up to and including 6.18.*not affected · semver
    • 6.19.9 and later · up to and including 6.19.*not affected · semver
    • 7.0 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.10-16.19.10-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-43481May 13, 2026 · net-shapers: don't free reply skb after genlmsg_reply()
    31Monitor
  • ← EarlierCVE-2026-43482May 13, 2026 · sched_ext: Disable preemption between scx_claim_exit() and kicking helper work
    22Monitor
  • Later →CVE-2026-43489May 13, 2026 · liveupdate: luo_file: remember retrieve() status
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux05d239f2c95e66e27e7fb4e99ee07eb56e3e34b0Vendor (CNA)
Linux Linux09d620555e59768776090073a2c59d2bc8506eb3Vendor (CNA)
Linux Linux6f92a7a8b48a523f910ef25dd83808710724f59bVendor (CNA)
Linux Linux97c5550b763171dbef61e6239cab372b9f9cd4a2Vendor (CNA)
debian:linux6.12.85-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-3144821 days apartext4: avoid infinite loops caused by residual data
    37Monitor
  • CVE-2026-6388967 days apartscsi: scsi_transport_fc: Widen FPIN pname walker counter to u32
    32Monitor
  • CVE-2026-5293342 days apartio_uring/poll: fix signed comparison in io_poll_get_ownership()
    31Monitor
  • CVE-2026-4605214 days apartceph: only d_add() negative dentries when they are unhashed
    30Monitor
  • CVE-2026-3155219 days apartwifi: wlcore: Return -ENOMEM instead of -EAGAIN if there is not enough headroom
    30Monitor
  • CVE-2026-2345140 days apartbonding: prevent potential infinite loop in bond_header_parse()
    30Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records