Review reviewHigh

CVE-2021-20322

kernel, linux kernel, fedora

A flaw in the processing of received ICMP errors (ICMP fragment needed and ICMP redirect) in the Linux kernel functionality was found to allow the ability to quickly scan open UDP ports. This flaw allows an off-path remote user to effectively bypass the source port UDP randomization. The highest threat from this vulnerability is to confidentiality and possibly integrity, because software that relies on UDP source port randomization are indirectly affected as well.

CVSS: 7.4
EPSS: 6.85%
CISA KEV: Not listed
Published: 2022.02.19

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability6.85%

Technical severityCVSS 7.4

Vulnerability overview

Affected product and versions

Product: kernel, linux kernel, fedora
Affected versions: >= 4.15 < 4.19.215, >= 4.20 < 5.4.146, >= 5.5 < 5.10.65, >= 5.11 < 5.13.17, >= 5.14 < 5.14.4, >= 4.20 < 5.4.157, >= 5.5 < 5.10.62, >= 5.11 < 5.13.14, 34, 9.0, 10.0, >= 11.0 <= 11.70.1, 22.1.3, 22.1.1, 22.2.0
Fixed versions: 4.19.215, 5.4.157, 5.10.62, 5.13.14

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that kernel, linux kernel, fedora and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE: CWE-330