Debian Long Term Support / LTS Security Information / 2021 / Security Information -- DLA-2753-1 qemu

Debian Security Advisory

DLA-2753-1 qemu -- LTS security update

Date Reported:

02 Sep 2021

Affected Packages:

qemu

Vulnerable:

Yes

Security database references:

In the Debian bugtracking system: Bug 988157, Bug 989993, Bug 989995, Bug 989996, Bug 991911, Bug 992727.
In Mitre's CVE dictionary: CVE-2021-3527, CVE-2021-3592, CVE-2021-3594, CVE-2021-3595, CVE-2021-3682, CVE-2021-3713.

More information:

Several security vulnerabilities have been found in Qemu, a fast processor emulator.

• CVE-2021-3713

  An out-of-bounds write flaw was found in the UAS (USB Attached SCSI) device emulation of QEMU. The device uses the guest supplied stream number unchecked, which can lead to out-of-bounds access to the UASDevice->data3 and UASDevice->status3 fields. A malicious guest user could use this flaw to crash QEMU or potentially achieve code execution with the privileges of the QEMU process on the host.

• CVE-2021-3682

  A flaw was found in the USB redirector device emulation of QEMU. It occurs when dropping packets during a bulk transfer from a SPICE client due to the packet queue being full. A malicious SPICE client could use this flaw to make QEMU call free() with faked heap chunk metadata, resulting in a crash of QEMU or potential code execution with the privileges of the QEMU process on the host.

• CVE-2021-3527

  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.

• CVE-2021-3594

  An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp_input() function and could occur while processing a udp packet that is smaller than the size of the udphdr structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality.

• CVE-2021-3592

  An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the bootp_input() function and could occur while processing a udp packet that is smaller than the size of the bootp_t structure. A malicious guest could use this flaw to leak 10 bytes of uninitialized heap memory from the host. The highest threat from this vulnerability is to data confidentiality.

• CVE-2021-3595

  An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the tftp_input() function and could occur while processing a udp packet that is smaller than the size of the tftp_t structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality.

For Debian 9 stretch, these problems have been fixed in version 1:2.8+dfsg-6+deb9u15.

We recommend that you upgrade your qemu packages.

For the detailed security status of qemu please refer to its security tracker page at: https://security-tracker.debian.org/tracker/qemu

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS