Several vulnerabilities were discovered in qemu, a fast processor emulator.
Tuomas Tynkkynen discovered an information leak in 9pfs.
Eric Blake discovered that the NBD server insufficiently restricts large option requests, resulting in denial of service.
Daniel Berrange discovered that the integrated VNC server insufficiently restricted memory allocation, which could result in denial of service.
A memory leak in websockets support may result in denial of service.
Guoxiang Niu discovered an OOB write in the emulated Cirrus graphics adaptor which could result in denial of service.
Cyrille Chatras discovered an information leak in PS/2 mouse and keyboard emulation which could be exploited during instance migration.
Dengzhan Heyuandong Bijunhua and Liweichao discovered that an implementation error in the virtio vring implementation could result in denial of service.
Eric Blake discovered an integer overflow in an internally used macro which could result in denial of service.
Jiang Xin and Lin ZheCheng discovered an OOB memory access in the emulated VGA adaptor which could result in denial of service.
Cyrille Chatras discovered that an OOB memory write when using multiboot could result in the execution of arbitrary code.
This update also backports a number of mitigations against the Spectre v2 vulnerability affecting modern CPUs (CVE-2017-5715). For additional information please refer to https://www.qemu.org/2018/01/04/spectre/
For the stable distribution (stretch), these problems have been fixed in version 1:2.8+dfsg-6+deb9u4.