CVE-2016-9386
The x86 emulator in Xen does not properly treat x86 NULL segments as unusable when accessing memory, which might allow local HVM guest users to gain privileges via vectors involving "unexpected" base/limit values.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.45%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
The x86 emulator in Xen does not properly treat x86 NULL segments as unusable when accessing memory, which might allow local HVM guest users to gain privileges via vectors involving "unexpected" base/limit values.
- CVSS 3.0
- 7.8 HIGHCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.45% probability · 39th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-264
- Affected
- citrix/xenserver · xen/xen
- Source
- cve@mitre.org
EPSS 0.4% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securityfocus.com/bid/94471Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1037340Third Party Advisory, VDB Entry
- http://xenbits.xen.org/xsa/advisory-191.htmlPatch, Vendor Advisory
- https://security.gentoo.org/glsa/201612-56
- https://support.citrix.com/article/CTX218775Patch, Third Party Advisory
- http://www.securityfocus.com/bid/94471Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1037340Third Party Advisory, VDB Entry
- http://xenbits.xen.org/xsa/advisory-191.htmlPatch, Vendor Advisory
- https://security.gentoo.org/glsa/201612-56
- https://support.citrix.com/article/CTX218775Patch, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.