Bug 2436828 (CVE-2026-23085) - CVE-2026-23085 kernel: irqchip/gic-v3-its: Avoid truncating memory addresses
Summary: CVE-2026-23085 kernel: irqchip/gic-v3-its: Avoid truncating memory addresses
Keywords:
Status: NEW
Alias: CVE-2026-23085
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-02-04 17:05 UTC by OSIDB Bzimport
Modified: 2026-02-05 16:34 UTC (History)
0 users

Fixed In Version:
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Description OSIDB Bzimport 2026-02-04 17:05:23 UTC
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.


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