Xen
CVE-2017-12855
MEDIUM
Severity by source
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Lifecycle Timeline
1DescriptionCVE.org
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.
AnalysisAI
Xen maintains the _GTF_{read,writ}ing bits as appropriate, to inform the guest that a grant is in use. Rated medium severity (CVSS 6.5), this vulnerability is low attack complexity. No vendor patch available.
Technical ContextAI
This vulnerability is classified as Exposure of Sensitive Information (CWE-200), which allows attackers to access sensitive data that should not be disclosed. 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. Affected products include: Xen.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Minimize information in error messages, implement proper access controls, encrypt sensitive data at rest and in transit.
The x86-64 kernel system-call functionality in Xen 4.1.2 and earlier, as used in Citrix XenServer 6.0.2 and earlier and
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The C+ mode offload emulation in the RTL8139 network card device model in QEMU, as used in Xen 4.5.x and earlier, allows
Xen, when used on a system providing PV backends, allows local guest OS administrators to cause a denial of service (hos
x86 pv: Insufficient care with non-coherent mappings T[his CNA information record relates to multiple CVEs; the text exp
Xen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to obt
Xen through 4.8.x mishandles page transfer, which allows guest OS users to obtain privileged host OS access, aka XSA-217
The grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and GNTMAP_h
Same weakness CWE-200 – Information Exposure
View allSame technique Information Disclosure
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External POC / Exploit Code
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