CVE-2021-29650

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-03-30 · updated 2026-06-17

Description

An issue was discovered in the Linux kernel before 5.11.11. The netfilter subsystem allows attackers to cause a denial of service (panic) because net/netfilter/x_tables.c and include/linux/netfilter/x_tables.h lack a full memory barrier upon the assignment of a new table value, aka CID-175e476b8cdf.

Affected products

Debian Linux: 9.0
Fedoraproject Fedora: 32, 33, 34
Linux kernel: before 5.11.11 — fixed in 5.11.11

How to fix

Upgrade to a fixed version: Linux kernel 5.11.11. Check the vendor advisory for mitigations.

References

https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.11
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=175e476b8cdf2a4de7432583b49c871345e4f8a1
https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html
https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RZGMUP6QEHJJEKPMLKOSPWYMW7PXFC2M/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VTADK5ELGTATGW2RK3K5MBJ2WGYCPZCM/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WKRNELXLVFDY6Y5XDMWLIH3VKIMQXLLR/
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.11
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=175e476b8cdf2a4de7432583b49c871345e4f8a1
https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html
https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RZGMUP6QEHJJEKPMLKOSPWYMW7PXFC2M/

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