CVE-2021-26932 Information

Description

An issue was discovered in the Linux kernel 3.2 through 5.10.16 as used by Xen. Grant mapping operations often occur in batch hypercalls where a number of operations are done in a single hypercall the success or failure of each one is reported to the backend driver and the backend driver then loops over the results performing follow-up actions based on the success or failure of each operation. Unfortunately when running in PV mode the Linux backend drivers mishandle this: Some errors are ignored effectively implying their success from the success of related batch elements. In other cases errors resulting from one batch element lead to further batch elements not being inspected and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch//xen/p2m.c and drivers/xen/gntdev.c.

CVSS Vector

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

Reference

http://xenbits.xen.org/xsa/advisory-361.html https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2XQR52ICKRK3GC4HDWLMWF2U55YGAR63/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GWQWPWYZRXVFJI5M3VCM72X27IB7CKOB/ https://lists.debian.org/debian-lts-announce/2021/03/msg00010.html https://security.netapp.com/advisory/ntap-20210326-0001/ https://lists.debian.org/debian-lts-announce/2021/03/msg00035.html

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5