Buffer overflow in Xen
CVE-2020-15564
An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash because of a missing alignment check in VCPUOP_register_vcpu_info. The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions that require a specific alignment. Unfortunately, there is no check that the address provided by the guest will be correctly aligned. As a result, a malicious guest could cause a hypervisor crash by passing a misaligned address. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). All Xen versions are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (31.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 31.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Xen
- Debian Linux — versions 10.0
- Fedoraproject Fedora — versions 31, 32
Weakness classification (CWE)
References
- xenbits.xen.org/xsa/advisory-327.html (Patch, Third Party Advisory)
- www.openwall.com/lists/oss-security/2020/07/07/5 (mailing-list, Patch, Mailing List, Third Party Advisory)
- www.debian.org/security/2020/dsa-4723 (vendor-advisory, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- security.gentoo.org/glsa/202007-02 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2020-15564?
- CVE-2020-15564 is a medium-severity vulnerability in Xen, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 6.5/10. Published 2020-07-07.
- How severe is CVE-2020-15564?
- Medium severity. CVSS v3 base score is 6.5 out of 10.