pci_change_irq_level in hw/pci/pci.c in QEMU before 5.1.1 has a NULL pointer dereference because pci_get_bus() might not return a valid pointer.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-25742
Reference (s):
- http://www.openwall.com/lists/oss-security/2020/09/29/1
- https://bugzilla.redhat.com/show_bug.cgi?id=1883178
- https://lists.nongnu.org/archive/html/qemu-devel/2020-09/msg05294.html
- https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Flsi_nullptr1