#VU59085 Infinite loop in QEMU - CVE-2021-20257

Vulnerability identifier: #VU59085

Vulnerability risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-20257

CWE-ID: CWE-835

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
QEMU
Client/Desktop applications / Virtualization software

Vendor: QEMU

Description

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

The vulnerability exists due to infinite loop in the e1000 NIC emulator when processing transmits (tx) descriptors in process_tx_desc of QEMU. A remote user can consume all available CPU resources and cause denial of service conditions.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

QEMU: 6.0.0 - 6.1.0

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External links
https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg03595.html
https://bugzilla.redhat.com/show_bug.cgi?id=1930087

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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