What’s Vulnerable › Vulnerabilities

CVE-2026-98320: netfilter: flowtable: hold reference on ct until flow is released

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-06 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: hold reference on ct until flow is released nf_ct_put() releases the ct->ext area inmediately, the rcu typesafe semantics also allow to refer to the wrong conntrack from the flowtable datapath. Hold reference on ct until flow is released after rcu grace period. Add rcu_barrier() on module exit path, to ensure pending flow entries are release before module goes away.

Affected products

• Linux kernel: 4.16 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/12c1ac230f4ca16e0017b62a963ab75e0b48074f
• https://git.kernel.org/stable/c/61c6688be282277c6e91ab286a7acd0ae8681ac6
• https://git.kernel.org/stable/c/8274cdc5f9c57e17ed77fc4ba76212536c840f25
• https://git.kernel.org/stable/c/93ff1594be1aad4da364462dd8db050ebcfda2de
• https://git.kernel.org/stable/c/a43cd2b67b91e943273c913237a7a88c50cdcfbc
• https://git.kernel.org/stable/c/d9e6175a3ee48209ee65f294fc567b4e16b29b74
• https://git.kernel.org/stable/c/e75a9fa1d44bcbd66ea02e8781bcca6ea4076e0d
• https://git.kernel.org/stable/c/eed6997e8dc40593a539fcc722e7ed51b18db86c

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