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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.

Published
Last modified
published
Not listed in CISA KEV
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • n/a n/a

    Version range not reported

References 9

xenbits.xen.org

openwall.com

lists.opensuse.org

lists.fedoraproject.org

debian.org

seclists.org

security.gentoo.org