Race condition in Xen - CVE-2019-19580

Vulnerability details

The vulnerability allows a local user to escalate privileges on the system.

An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by leveraging race conditions in pagetable promotion and demotion operations, because of an incomplete fix for CVE-2019-18421. XSA-299 addressed several critical issues in restartable PV type change operations. Despite extensive testing and auditing, some corner cases were missed. A malicious PV guest administrator may be able to escalate their privilege to that of the host. All security-supported versions of Xen are vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can leverage the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Note that these attacks require very precise timing, which may be difficult to exploit in practice.

Affected software

How to mitigate CVE-2019-19580

External References

• http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00011.html
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/34HBFTYNMQMWIO2GGK7DB6KV4M6R5YPV/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/D5R73AYE53QA32KTMHUVKCX6E52CIS43/
• https://seclists.org/bugtraq/2020/Jan/21
• https://security.gentoo.org/glsa/202003-56
• https://www.debian.org/security/2020/dsa-4602
• https://xenbits.xen.org/xsa/advisory-310.html

Related Security Bulletins

• Multiple vulnerabilities in Xen
• OpenSUSE Linux update for xen
• Race condition in xen (Alpine package)
• Gentoo update for Xen
• Debian update for xen
• Fedora 31 update for xen
• Fedora 30 update for xen