#VU31805 Reachable Assertion in QEMU - CVE-2020-10761

Vulnerability identifier: #VU31805

Vulnerability risk: Medium

CVSSv4.0: 6.6 [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/E:U/U:Green]

CVE-ID: CVE-2020-10761

CWE-ID: CWE-617

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
QEMU
Client/Desktop applications / Virtualization software

Vendor: QEMU

Description

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.

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

Vulnerable software versions

QEMU: 0.1 - 5.0.0

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

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.