CVE-2017-12855

What it is

Xen maintains the _GTF_{read,writ}ing bits as appropriate, to inform the guest that a grant is in use. A guest is expected not to modify the grant details while it is in use, whereas the guest is free to modify/reuse the grant entry when it is not in use. Under some circumstances, Xen will clear the status bits too early, incorrectly informing the guest that the grant is no longer in use. A guest may prematurely believe that a granted frame is safely private again, and reuse it in a way which contains sensitive information, while the domain on the far end of the grant is still using the grant. Xen 4.9, 4.8, 4.7, 4.6, and 4.5 are affected.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2017-08-15 16:29 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 01:04 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 6.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2017-08-15 16:29 UTC

Last modified

2026-06-17 01:04 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-200 · Information exposure

Record status

Modified

Affected

• Xen 4.5.0
• Xen 4.5.1
• Xen 4.5.2
• Xen 4.5.3
• Xen 4.5.5
• Xen 4.6.0
• Xen 4.6.1
• Xen 4.6.3

Attack profile CVSS 3.0 · 6.5

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2017-12855.md and follow it. Check whether this project is affected by CVE-2017-12855. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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