CVE-2021-20177

4.4 mediumEPSS 0.3%

Medium (4.4) in linux linux kernel. EPSS 0.3% chance of exploitation in the next 30 days.

A flaw was found in the Linux kernel's implementation of string matching within a packet. A privileged user (with root or CAP_NET_ADMIN) when inserting iptables rules could insert a rule which can panic the system. Kernel before kernel 5.5-rc1 is affected.

Severity

CVSS 3.1

4.4 medium

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

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 20% of CVEs (scores of 2026-10-31)
CWE: CWE-125
Published: 2021-05-26
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

linux:linux_kernel

References

https://bugzilla.redhat.com/show_bug.cgi?id=1914719
https://bugzilla.redhat.com/show_bug.cgi?id=1914719

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