CVE-2021-20322

Medium

Elevated severity or exploit probability.

CVSS base

7.4 HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — probability of exploitation (30 days)

6.8%

93.7th percentile

CISA KEV

Not listed

Weakness / dates

CWE-330

Published 2022-02-18 · modified 2026-07-30

CVSS breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector	N	Network
Attack Complexity	H	High
Privileges Required	N	None
User Interaction	N	None
Scope	U	Unchanged
Confidentiality	H	High
Integrity	H	High
Availability	N	None

Timeline

2022-02-18 — Published (NVD)
2026-07-30 — Last modified (NVD)

Description

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.

Affected

debian fedoraproject linux netapp oracle

References

Official: NVD · CVE.org