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CVE-2017-12855

UnknownEPSS 0.40%

Last modified

CVE-2017-12855 is a vulnerability of currently unknown severity. 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. EPSS estimates a 0.40% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.40%

31.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
XenXen4.5.0
XenXen4.5.1
XenXen4.5.2
XenXen4.5.3
XenXen4.5.5
XenXen4.6.0
XenXen4.6.1
XenXen4.6.3
XenXen4.6.4
XenXen4.6.5
XenXen4.6.6
XenXen4.7.0
XenXen4.7.1
XenXen4.7.2
XenXen4.7.3
XenXen4.8.0
XenXen4.8.1
XenXen4.9.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2017-12855?
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.
How severe is CVE-2017-12855?
Severity scoring for CVE-2017-12855 is pending analysis. The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.
How do I fix CVE-2017-12855?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST