CVE-2016-6833

Use-after-free vulnerability in the vmxnet3_io_bar0_write function in hw/net/vmxnet3.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (QEMU instance crash) by leveraging failure to check if the device is active.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• http://git.qemu.org/?p=qemu.git%3Ba=commit%3Bh=6c352ca9b4ee3e1e286ea9e8434bd8e69ac7d0d8
• http://www.openwall.com/lists/oss-security/2016/08/12/1
• http://www.openwall.com/lists/oss-security/2016/08/18/3
• http://www.securityfocus.com/bid/93255
• https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
• https://lists.gnu.org/archive/html/qemu-devel/2016-08/msg01602.html
• https://security.gentoo.org/glsa/201609-01
• http://git.qemu.org/?p=qemu.git%3Ba=commit%3Bh=6c352ca9b4ee3e1e286ea9e8434bd8e69ac7d0d8
• http://www.openwall.com/lists/oss-security/2016/08/12/1
• http://www.openwall.com/lists/oss-security/2016/08/18/3
• http://www.securityfocus.com/bid/93255
• https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
• https://lists.gnu.org/archive/html/qemu-devel/2016-08/msg01602.html
• https://security.gentoo.org/glsa/201609-01