CVE-2026-52998

Description

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.

CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0051

Probability of exploitation

0.40%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/5d05de2f0928d81309a815ecc76d1a3ad72cbc16 https://git.kernel.org/stable/c/711987ba281fd806322a7cd244e98e2a81903114 https://git.kernel.org/stable/c/79b90a96688e521771fa6ed3dc7864b76b8df293 https://git.kernel.org/stable/c/83fc5dd63455a779ea2dd0f7ffee3c920919d80b https://git.kernel.org/stable/c/95be653a76793856ff8b2d8bd82c2943c23f5ca8 https://git.kernel.org/stable/c/c996a90f3071cf43683e5423da31aadbe002b8b4 https://git.kernel.org/stable/c/edc806f9122961f0d3819f7c69c14cccde31f277 https://git.kernel.org/stable/c/f4de0777e4554a7de19c920accde6319dd530782

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-52998? +

CVE-2026-52998 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0051, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-52998? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.