8.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.5 High
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:M/Au:S/C:C/I:C/A:C
0.009 Low
EPSS
Percentile
82.5%
p2m->max_mapped_gfn is used by the functions p2m_resolve_translation_fault() and p2m_get_entry() to sanity check guest physical frame. The rest of the code in the two functions will assume that there is a valid root table and check that with BUG_ON().
The function p2m_get_root_pointer() will ignore the unused top bits of a guest physical frame. This means that the function p2m_set_entry() will alias the frame. However, p2m->max_mapped_gfn will be updated using the original frame.
It would be possible to set p2m->max_mapped_gfn high enough to cover a frame that would lead p2m_get_root_pointer() to return NULL in p2m_get_entry() and p2m_resolve_translation_fault().
Additionally, the sanity check on p2m->max_mapped_gfn is off-by-one allowing “highest mapped + 1” to be considered valid. However, p2m_get_root_pointer() will return NULL.
The problem could be triggered with a specially crafted hypercall XENMEM_add_to_physmap{, _batch} followed by an access to an address (via hypercall or direct access) that passes the sanity check but cause p2m_get_root_pointer() to return NULL.
A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS).
Xen version 4.8 and newer are vulnerable.
Only Arm systems are vulnerable. x86 systems are not affected.
8.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.5 High
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:M/Au:S/C:C/I:C/A:C
0.009 Low
EPSS
Percentile
82.5%