Reachable Assertion in QEMU - CVE-2020-10761

Vulnerability identifier: #VU31805

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2020-10761

CWE-ID: CWE-617

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a reachable assertion in the Network Block Device(NBD) Server. This flaw occurs when an nbd-client sends a spec-compliant request that is near the boundary of maximum permitted request length. A remote nbd-client could use this flaw to crash the qemu-nbd server resulting in a denial of service.

QEMU
Gentoo Linux
Opensuse
Ubuntu
qemu-system-ppc (Ubuntu package)
qemu-system-aarch64 (Ubuntu package)
qemu-system-x86 (Ubuntu package)
qemu-system-sparc (Ubuntu package)
qemu-system-s390x (Ubuntu package)
qemu-system-mips (Ubuntu package)
qemu-system-arm (Ubuntu package)
qemu (Ubuntu package)
qemu-system (Ubuntu package)
qemu-system-x86-microvm (Ubuntu package)
qemu-system-x86-xen (Ubuntu package)

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

qemu-system-ppc (Ubuntu package) - addressed in versions 1:2.5+dfsg-5ubuntu10.45, 1:2.11+dfsg-1ubuntu7.31, 1:4.2-3ubuntu6.4
qemu-system-aarch64 (Ubuntu package) - update to 1:2.5+dfsg-5ubuntu10.45
qemu-system-x86 (Ubuntu package) - addressed in versions 1:2.5+dfsg-5ubuntu10.45, 1:2.11+dfsg-1ubuntu7.31, 1:4.2-3ubuntu6.4
qemu-system-sparc (Ubuntu package) - addressed in versions 1:2.5+dfsg-5ubuntu10.45, 1:2.11+dfsg-1ubuntu7.31, 1:4.2-3ubuntu6.4
qemu-system-s390x (Ubuntu package) - addressed in versions 1:2.5+dfsg-5ubuntu10.45, 1:2.11+dfsg-1ubuntu7.31, 1:4.2-3ubuntu6.4
qemu-system-mips (Ubuntu package) - addressed in versions 1:2.5+dfsg-5ubuntu10.45, 1:2.11+dfsg-1ubuntu7.31, 1:4.2-3ubuntu6.4
qemu-system-arm (Ubuntu package) - addressed in versions 1:2.5+dfsg-5ubuntu10.45, 1:4.2-3ubuntu6.4
qemu (Ubuntu package) - addressed in versions 1:2.5+dfsg-5ubuntu10.45, 1:2.11+dfsg-1ubuntu7.31, 1:4.2-3ubuntu6.4
qemu-system (Ubuntu package) - addressed in versions 1:2.5+dfsg-5ubuntu10.45, 1:2.11+dfsg-1ubuntu7.31, 1:4.2-3ubuntu6.4
qemu-system-x86-microvm (Ubuntu package) - update to 1:4.2-3ubuntu6.4
qemu-system-x86-xen (Ubuntu package) - update to 1:4.2-3ubuntu6.4

• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-10761
• https://www.openwall.com/lists/oss-security/2020/06/09/1

• Multiple vulnerabilities in QEMU
• OpenSUSE Linux update for qemu
• Gentoo update for QEMU
• Ubuntu update for qemu