Vulnerability Details : CVE-2021-46975
In the Linux kernel, the following vulnerability has been resolved:
netfilter: conntrack: Make global sysctls readonly in non-init netns
These sysctls point to global variables:
- NF_SYSCTL_CT_MAX (&nf_conntrack_max)
- NF_SYSCTL_CT_EXPECT_MAX (&nf_ct_expect_max)
- NF_SYSCTL_CT_BUCKETS (&nf_conntrack_htable_size_user)
Because their data pointers are not updated to point to per-netns
structures, they must be marked read-only in a non-init_net ns.
Otherwise, changes in any net namespace are reflected in (leaked into)
all other net namespaces. This problem has existed since the
introduction of net namespaces.
The current logic marks them read-only only if the net namespace is
owned by an unprivileged user (other than init_user_ns).
Commit d0febd81ae77 ("netfilter: conntrack: re-visit sysctls in
unprivileged namespaces") "exposes all sysctls even if the namespace is
unpriviliged." Since we need to mark them readonly in any case, we can
forego the unprivileged user check altogether.
Products affected by CVE-2021-46975
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Exploit prediction scoring system (EPSS) score for CVE-2021-46975
0.04%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 7 %
Percentile, the proportion of vulnerabilities that are scored at or less
References for CVE-2021-46975
-
https://git.kernel.org/stable/c/d3598eb3915cc0c0d8cab42f4a6258ff44c4033e
netfilter: conntrack: Make global sysctls readonly in non-init netns - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/2671fa4dc0109d3fb581bc3078fdf17b5d9080f6
netfilter: conntrack: Make global sysctls readonly in non-init netns - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/fbf85a34ce17c4cf0a37ee253f4c582bbfb8231b
netfilter: conntrack: Make global sysctls readonly in non-init netns - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/9b288479f7a901a14ce703938596438559d7df55
netfilter: conntrack: Make global sysctls readonly in non-init netns - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/da50f56e826e1db141693297afb99370ebc160dd
netfilter: conntrack: Make global sysctls readonly in non-init netns - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/671c54ea8c7ff47bd88444f3fffb65bf9799ce43
netfilter: conntrack: Make global sysctls readonly in non-init netns - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/68122479c128a929f8f7bdd951cfdc8dd0e75b8f
netfilter: conntrack: Make global sysctls readonly in non-init netns - kernel/git/stable/linux.git - Linux kernel stable tree
-
https://git.kernel.org/stable/c/baea536cf51f8180ab993e374cb134b5edad25e2
netfilter: conntrack: Make global sysctls readonly in non-init netns - kernel/git/stable/linux.git - Linux kernel stable tree
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