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High severity · published May 1, 2026
CVE-2026-43025
netfilter: ctnetlink: ignore explicit helper on new expectations
7.3
CVSS
0.1%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: ignore explicit helper on new expectations Use the existing master conntrack helper, anything else is not really supported and it just makes validation more complicated, so just ignore what helper userspace suggests for this expectation. This was uncovered when validating CTA_EXPECT_CLASS via different helper provided by userspace than the existing master conntrack helper: BUG: KASAN: slab-out-of-bounds in nf_ct_expect_related_report+0x2479/0x27c0 Read of size 4 at addr ffff8880043fe408 by task poc/102 Call Trace: nf_ct_expect_related_report+0x2479/0x27c0 ctnetlink_create_expect+0x22b/0x3b0 ctnetlink_new_expect+0x4bd/0x5c0 nfnetlink_rcv_msg+0x67a/0x950 netlink_rcv_skb+0x120/0x350 Allowing to read kernel memory bytes off the expectation boundary. CTA_EXPECT_HELP_NAME is still used to offer the helper name to userspace via netlink dump.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
Low
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 2% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
3.12 before 6.1.168; 6.2 before 6.6.134; 6.7 before 6.12.81; 6.13 before 6.18.22; 6.19 before 6.19.12; 7.0; +5 more · source: NVD
LI
Linux · Linux
bd0779370588386e4a67ba5d0b176cfded8e6a53 before e135f8e8212cbed12a03ab8dec77fa1247139897; bd0779370588386e4a67ba5d0b176cfded8e6a53 before 2ea0f35f235f70c133ad61fe05ba013753b978c6; bd0779370588386e4a67ba5d0b176cfded8e6a53 before 0f6c33697ccfac6499d0b7a4dbdec5d3a3a566cd; bd0779370588386e4a67ba5d0b176cfded8e6a53 before 187b6ec5229ea93cb04c4f6d3b52efc80f513d0d; bd0779370588386e4a67ba5d0b176cfded8e6a53 before 21a04c31db4057deec85fcd6cc63d720b38819c3; bd0779370588386e4a67ba5d0b176cfded8e6a53 before 917b61fa2042f11e2af4c428e43f08199586633a; +1 more · source: vendor
SS
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.6; V3.1.5; V3.1.7; V3.1.6; V3.1.5; V3.1.7 · source: CISA
SS
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP · Siemens
V3.1.6; V3.1.5; V3.1.7; V3.1.6; V3.1.5; V3.1.7 · source: CISA
SS
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.6; V3.1.5; V3.1.7 · source: CISA
Affected product
KE
Kernel
Linux
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-43025
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-43025
Patch
https://git.kernel.org/stable/c/0f6c33697ccfac6499d0b7a4dbdec5d3a3a566cd
Patch
https://git.kernel.org/stable/c/187b6ec5229ea93cb04c4f6d3b52efc80f513d0d
Patch
https://git.kernel.org/stable/c/21a04c31db4057deec85fcd6cc63d720b38819c3
Patch
https://git.kernel.org/stable/c/2ea0f35f235f70c133ad61fe05ba013753b978c6
Patch
https://git.kernel.org/stable/c/917b61fa2042f11e2af4c428e43f08199586633a
Patch
https://git.kernel.org/stable/c/e135f8e8212cbed12a03ab8dec77fa1247139897
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