ALPINE-CVE-2019-18420

Advisory lineage Upstream: 1 Downstream: 0
Upstream
CVE-2019-18420
Published: 31 Oct 2019, 14:15
Last modified:19 Nov 2025, 06:15

Vulnerability Summary

Overall Risk (default)
medium
26/100
CVSS Score
6.5 MEDIUM
3.1 (osv_alpine)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

31 Oct 2019, 14:15
Published
Vulnerability first disclosed
19 Nov 2025, 06:15
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•MEDIUM•Score: 6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Systems

  • alpine•xen

    < 4.11.2-r0

References (1)