CVE-2017-12855

LOW

Description

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.

References

http://www.debian.org/security/2017/dsa-3969

http://www.securityfocus.com/bid/100341

http://www.securitytracker.com/id/1039177

http://xenbits.xen.org/xsa/advisory-230.html

https://support.citrix.com/article/CTX225941

Details

Source: MITRE

Published: 2017-08-15

Updated: 2017-11-15

Type: CWE-200

Risk Information

CVSS v2.0

Base Score: 2.1

Vector: AV:L/AC:L/Au:N/C:P/I:N/A:N

Impact Score: 2.9

Exploitability Score: 3.9

Severity: LOW

CVSS v3.0

Base Score: 6.5

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Impact Score: 4

Exploitability Score: 2

Severity: MEDIUM