What’s Vulnerable › Vulnerabilities

CVE-2020-36694

• Severity: medium (CVSS 6.7 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: yes
• Published: 2023-05-21 · updated 2026-06-17
• Weakness: CWE-416

Description

An issue was discovered in netfilter in the Linux kernel before 5.10. There can be a use-after-free in the packet processing context, because the per-CPU sequence count is mishandled during concurrent iptables rules replacement. This could be exploited with the CAP_NET_ADMIN capability in an unprivileged namespace. NOTE: cc00bca was reverted in 5.12.

Affected products

• Linux kernel: before 5.10 — fixed in 5.10

How to fix

Upgrade to a fixed version: Linux kernel 5.10. Check the vendor advisory for mitigations.

References

• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cc00bcaa589914096edef7fb87ca5cee4a166b5c
• https://security.netapp.com/advisory/ntap-20230622-0005/
• https://syzkaller.appspot.com/bug?id=0c4fd9c6aa04ec116d01e915d3b186f71a212cb2
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cc00bcaa589914096edef7fb87ca5cee4a166b5c
• https://security.netapp.com/advisory/ntap-20230622-0005/
• https://syzkaller.appspot.com/bug?id=0c4fd9c6aa04ec116d01e915d3b186f71a212cb2

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