CVE-2021-3527 Information

Description

A flaw was found in the USB redirector device (usb-redir) of QEMU. Small USB packets are combined into a single large transfer request to reduce the overhead and improve performance. The combined size of the bulk transfer is used to dynamically allocate a variable length array (VLA) on the stack without proper validation. Since the total size is not bounded a malicious guest could use this flaw to influence the array length and cause the QEMU process to perform an excessive allocation on the stack resulting in a denial of service.

CVSS Vector

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

Reference

https://www.openwall.com/lists/oss-security/2021/05/05/5 https://gitlab.com/qemu-project/qemu/-/commit/05a40b172e4d691371534828078be47e7fff524c https://bugzilla.redhat.com/show_bug.cgi?id=1955695 https://gitlab.com/qemu-project/qemu/-/commit/7ec54f9eb62b5d177e30eb8b1cad795a5f8d8986 https://security.netapp.com/advisory/ntap-20210708-0008/ https://lists.debian.org/debian-lts-announce/2021/09/msg00000.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