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CVE Record

CVE-2026-23085: irqchip/gic-v3-its: Avoid truncating memory addresses

In the Linux kernel, the following vulnerability has been resolved: irqchip/gic-v3-its: Avoid truncating memory addresses On 32-bit machines with CONFIG_ARM_LPAE, it is possible for lowmem allocations to be backed by addresses physical memory above the 32-bit address limit, as found while experimenting with larger VMSPLIT configurations. This caused the qemu virt model to crash in the GICv3 driver, which allocates the 'itt' object using GFP_KERNEL. Since all memory below the 4GB physical address limit is in ZONE_DMA in this configuration, kmalloc() defaults to higher addresses for ZONE_NORMAL, and the ITS driver stores the physical address in a 32-bit 'unsigned long' variable. Change the itt_addr variable to the correct phys_addr_t type instead, along with all other variables in this driver that hold a physical address. The gicv5 driver correctly uses u64 variables, while all other irqchip drivers don't call virt_to_phys or similar interfaces. It's expected that other device drivers have similar issues, but fixing this one is sufficient for booting a virtio based guest.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can crash certain 32-bit ARM systems when memory above the 4GB physical boundary is mishandled by the GICv3 ITS interrupt driver. The described impact is stability and boot failure, especially in QEMU virt-style guests, not confirmed data theft or remote takeover.

Executive priority

Treat this as a targeted reliability risk for specific ARM virtualization environments, not an enterprise-wide emergency based on current evidence. Patch through normal kernel maintenance unless critical ARM LPAE guests are crashing or blocking operations.

Technical view

The GICv3 ITS driver stored physical addresses in unsigned long, which truncates addresses on 32-bit ARM systems using CONFIG_ARM_LPAE. When lowmem allocations are backed by physical memory above 32 bits, the driver can use an invalid ITS table address. The fix changes address-holding variables to phys_addr_t.

Likely exposure

Exposure appears limited to Linux kernels on 32-bit ARM LPAE configurations using the GICv3 ITS path, especially virtualized environments with physical addresses above 4GB. General x86 servers and unrelated irqchip drivers are not indicated as affected in the supplied sources.

Exploitation context

The supplied record does not show active exploitation, public exploit use, KEV listing, CVSS scoring, or a weaponized attack path. The evidence describes a crash discovered during larger VMSPLIT experimentation and sufficient fixing to boot a virtio-based guest.

Researcher notes

The root cause is type width mismatch for physical addresses in irqchip/gic-v3-its. The source notes gicv5 already used wider variables and other irqchip drivers do not call virt_to_phys-like interfaces. Similar issues may exist elsewhere, but this CVE evidence only supports this driver.

Mitigation direction

  • Review vendor kernel advisories for CVE-2026-23085 and applicable stable updates.
  • Prioritize updating affected Linux kernel branches that include the referenced stable fixes.
  • Check 32-bit ARM LPAE virtualized systems using GICv3 ITS before broader rollout.
  • If updates are unavailable, consult vendor guidance for supported configuration workarounds.

Validation and detection

  • Inventory Linux systems running 32-bit ARM kernels with CONFIG_ARM_LPAE enabled.
  • Identify systems using GICv3 ITS, especially QEMU virt or virtio-based guests.
  • Compare deployed kernel versions against vendor packages containing the referenced stable commits.
  • Confirm post-update boot stability on representative ARM LPAE virtual machines.
Prepared
Confidence
medium
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2026-23085 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
1ADP providers
8Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxcc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7eunaffected
LinuxLinux3.19, 0, 5.10.249, 5.15.199, 6.1.162, 6.6.122, 6.12.68, 6.18.8, 6.19affected
Weakness

CWE details

No CWE listed

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