High 7.5Published Jun 24, 2026

CVE-2026-52998netfilter: nfnetlink_osf: fix potential NULL dereference in ttl check

Updated under an hour ago (Oct 28, 2026, 10:50 AM ET)

Does this affect you?

It affects Linux and 4 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for Linux

Exploited in the last 30 days

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: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-476
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before f4de0777e4554a7de19c920accde6319dd530782; from 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before c996a90f3071cf43683e5423da31aadbe002b8b4; from 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before edc806f9122961f0d3819f7c69c14cccde31f277; 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 builds before 5d05de2f0928d81309a815ecc76d1a3ad72cbc16; from 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 95be653a76793856ff8b2d8bd82c2943c23f5ca8; from 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 79b90a96688e521771fa6ed3dc7864b76b8df293; from 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 83fc5dd63455a779ea2dd0f7ffee3c920919d80b; from 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 before 711987ba281fd806322a7cd244e98e2a81903114	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 2.6.31 before 5.10.258; from 5.11 before 5.15.209; from 5.16 before 6.1.175; from 6.2 before 6.6.141; from 6.7 before 6.12.91; from 6.13 before 6.18.33; from 6.19 before 7.0.10	NVD

References

References

https://git.kernel.org/stable/c/f4de0777e4554a7de19c920accde6319dd530782	patch
https://git.kernel.org/stable/c/c996a90f3071cf43683e5423da31aadbe002b8b4	patch
https://git.kernel.org/stable/c/edc806f9122961f0d3819f7c69c14cccde31f277	patch
https://git.kernel.org/stable/c/5d05de2f0928d81309a815ecc76d1a3ad72cbc16	patch
https://git.kernel.org/stable/c/95be653a76793856ff8b2d8bd82c2943c23f5ca8	patch
https://git.kernel.org/stable/c/79b90a96688e521771fa6ed3dc7864b76b8df293	patch
https://git.kernel.org/stable/c/83fc5dd63455a779ea2dd0f7ffee3c920919d80b	patch
https://git.kernel.org/stable/c/711987ba281fd806322a7cd244e98e2a81903114	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-457936.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.