cbcvebase.
CVE-2019-18420
published 2019-10-31

CVE-2019-18420: An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service via a VCPUOP_initialise hypercall…

PriorityP432medium6.5CVSS 3.1
AVNACLPRLUINSUCNINAH
EPSS
2.52%
83.1th percentile
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service via a VCPUOP_initialise hypercall. hypercall_create_continuation() is a variadic function which uses a printf-like format string to interpret its parameters. Error handling for a bad format character was done using BUG(), which crashes Xen. One path, via the VCPUOP_initialise hypercall, has a bad format character. The BUG() can be hit if VCPUOP_initialise executes for a sufficiently long period of time for a continuation to be created. Malicious guests may cause a hypervisor crash, resulting in a Denial of Service (DoS). Xen versions 4.6 and newer are vulnerable. Xen versions 4.5 and earlier are not vulnerable. Only x86 PV guests can exploit the vulnerability. HVM and PVH guests, and guests on ARM systems, cannot exploit the vulnerability.

Affected

11 ranges
VendorProductVersion rangeFixed in
debiandebian_linux
debiandebian_linux
debianxen< xen 4.11.3+24-g14b62ab3e5-1 (bookworm)xen 4.11.3+24-g14b62ab3e5-1 (bookworm)
fedoraprojectfedora
fedoraprojectfedora
fedoraprojectfedora
xenxen<= 4.12.1
xenxen>= 0 < 4.11.3+24-g14b62ab3e5-14.11.3+24-g14b62ab3e5-1
xenxen>= 0 < 4.11.3+24-g14b62ab3e5-14.11.3+24-g14b62ab3e5-1
xenxen>= 0 < 4.11.3+24-g14b62ab3e5-14.11.3+24-g14b62ab3e5-1
xenxen>= 0 < 4.11.3+24-g14b62ab3e5-14.11.3+24-g14b62ab3e5-1

CVSS provenance

nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvdv2.06.3MEDIUMAV:N/AC:M/Au:S/C:N/I:N/A:C
osv6.5MEDIUM
vendor_debian6.5MEDIUM
vendor_redhat6.5MEDIUM
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