CVE-2019-18420

medium
New! CVE Severity Now Using CVSS v3

The calculated severity for CVEs has been updated to use CVSS v3 by default. CVEs that do not have a CVSS v3 score will fall back CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

Description

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.

References

http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.html

http://www.openwall.com/lists/oss-security/2019/10/31/1

http://xenbits.xen.org/xsa/advisory-296.html

https://lists.fedoraproject.org/archives/list/[email protected]/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/

https://lists.fedoraproject.org/archives/list/[email protected]/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/

https://lists.fedoraproject.org/archives/list/[email protected]/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/

https://seclists.org/bugtraq/2020/Jan/21

https://security.gentoo.org/glsa/202003-56

https://www.debian.org/security/2020/dsa-4602

Details

Source: MITRE

Published: 2019-10-31

Updated: 2020-08-24

Type: CWE-134

Risk Information

CVSS v2

Base Score: 6.3

Vector: AV:N/AC:M/Au:S/C:N/I:N/A:C

Impact Score: 6.9

Exploitability Score: 6.8

Severity: MEDIUM

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Impact Score: 3.6

Exploitability Score: 2.8

Severity: MEDIUM

Vulnerable Software

Configuration 1

OR

cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:* versions up to 4.12.1 (inclusive)

Tenable Plugins

View all (15 total)

IDNameProductFamilySeverity
150584SUSE SLES11 Security Update : xen (SUSE-SU-2020:14444-1)NessusSuSE Local Security Checks
critical
134964GLSA-202003-56 : Xen: Multiple vulnerabilities (MDSUM/RIDL) (MFBDS/RIDL/ZombieLoad) (MLPDS/RIDL) (MSBDS/Fallout)NessusGentoo Local Security Checks
critical
133763SUSE SLES12 Security Update : xen (SUSE-SU-2020:0388-1)NessusSuSE Local Security Checks
critical
133539SUSE SLES12 Security Update : xen (SUSE-SU-2020:0334-1)NessusSuSE Local Security Checks
critical
132875Debian DSA-4602-1 : xen - security update (MDSUM/RIDL) (MFBDS/RIDL/ZombieLoad) (MLPDS/RIDL) (MSBDS/Fallout)NessusDebian Local Security Checks
critical
132073SUSE SLES12 Security Update : xen (SUSE-SU-2019:3297-1)NessusSuSE Local Security Checks
critical
131460Fedora 30 : xen (2019-cbb732f760)NessusFedora Local Security Checks
critical
131143Fedora 31 : xen (2019-376ec5c107)NessusFedora Local Security Checks
critical
131098Fedora 29 : xen (2019-865bb16900)NessusFedora Local Security Checks
critical
131062openSUSE Security Update : xen (openSUSE-2019-2508)NessusSuSE Local Security Checks
critical
131060openSUSE Security Update : xen (openSUSE-2019-2506)NessusSuSE Local Security Checks
critical
130960SUSE SLED12 / SLES12 Security Update : xen (SUSE-SU-2019:2962-1)NessusSuSE Local Security Checks
critical
130959SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2019:2961-1)NessusSuSE Local Security Checks
critical
130958SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2019:2960-1)NessusSuSE Local Security Checks
critical
130759Xen Project VCPUOP_initialise DoS (XSA-296)NessusMisc.
medium