What is CVE-2021-20257?

CVE-2021-20257 is a medium-severity vulnerability in Qemu, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2022-03-16.

How severe is CVE-2021-20257?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2021-20257 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Qemu

CVE-2021-20257

An infinite loop flaw was found in the e1000 NIC emulator of the QEMU. This issue occurs while processing transmits (tx) descriptors in process_tx_desc if various descriptor fields are initialized with invalid values. This flaw allows a guest to consume CPU cycles on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

EPSS: 0.004 (29.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H.

Affected products

Qemu
Debian Debian_linux — versions 10.0
Fedoraproject Fedora — versions 33
Redhat Codeready_linux_builder
Redhat Enterprise_linux — versions 6.0, 8.0
Redhat Enterprise_linux_for_ibm_z_systems — versions 8.0
Redhat Enterprise_linux_for_power_little_endian — versions 8.0
Redhat Openstack_platform — versions 10.0, 13.0
N/a Qemu — versions Fixed-In v6.2.0

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

secalert@redhat.com (Patch, Mailing List, Third Party Advisory, x_refsource_MISC)
secalert@redhat.com (Patch, Mailing List, x_refsource_MISC, Vendor Advisory)
secalert@redhat.com (Patch, Third Party Advisory, x_refsource_MISC)
secalert@redhat.com (Patch, Third Party Advisory, x_refsource_MISC, Issue Tracking)
secalert@redhat.com (x_refsource_CONFIRM, Third Party Advisory)
secalert@redhat.com (vendor-advisory, Third Party Advisory, x_refsource_GENTOO)
secalert@redhat.com (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2021-20257?: CVE-2021-20257 is a medium-severity vulnerability in Qemu, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2022-03-16.
How severe is CVE-2021-20257?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2021-20257 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.