CVE-2026-52998
In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix potential NULL dereference in ttl check The nf_osf_ttl() function accessed skb->dev to perform a local interface address lookup without verifying that the device pointer was valid. Additionally, the implementation utilized an in_dev_for_each_ifa_rcu loop to match the packet source address against local interface addresses. It assumed that packets from the same subnet should not see a decrement on the initial TTL. A packet might appear it is from the same subnet but it actually isn't especially in modern environments with containers and virtual switching. Remove the device dereference and interface loop. Replace the logic with a switch statement that evaluates the TTL according to the ttl_check.
Affected versions
Linux kernel versions
2.6.31
and later are affected. Fixed in
5.10.258,
5.15.209,
6.1.175,
6.6.141,
6.12.91,
6.18.33,
7.0.10,
7.1
and their respective stable series.
References
8 totalFrequently asked questions
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What is CVE-2026-52998?
CVE-2026-52998 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 2.6.31 onward and has been patched in 5.10.258, 5.15.209, 6.1.175 and others. CVE-2026-52998 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-52998?
Yes — CVE-2026-52998 has been patched. Fixed versions include 5.10.258, 5.15.209, 6.1.175 and others. If you are running Linux kernel 2.6.31 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-52998 actively exploited?
No — CVE-2026-52998 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.