CVE-2021-38209: Linux Kernel

Low severity, CVSS 3.3. EPSS: 0.3% chance of exploitation in the next 30 days.

net/netfilter/nf_conntrack_standalone.c in the Linux kernel before 5.12.2 allows observation of changes in any net namespace because these changes are leaked into all other net namespaces. This is related to the NF_SYSCTL_CT_MAX, NF_SYSCTL_CT_EXPECT_MAX, and NF_SYSCTL_CT_BUCKETS sysctls.

Affected products

• Linux Linux Kernel: before 5.12.2 (fixed in 5.12.2)

Published 2021-08-08. Last modified 2026-06-17.