CVE-2026-43025
Published: May 1, 2026· Updated: May 3, 2026
Official 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.
Technical Analysis
CVE-2026-43025 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), availability disruption (denial of service), with a CVSS base score of 7.3.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
All References (6)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-43025 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts