EUVD Vulnerability Catalog

EUVD-2026-103730

Severity: CRITICAL Base Score: 9.8 CVSS Version: 3.1

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: conntrack: fix helper UAF due to extensions realloc While calling the helpers, a raw pointer to the extensions area is wired into expectations list: -> nf_ct_helper() -> helper->help() -> nf_ct_expect_related_report() -> nf_ct_expect_insert() -> hlist_add_head_rcu(&exp->lnode, &master_help->expectations) In case the connection is not confirmed yet, more extensions can be added afterwards with *_ext_add() calls reallocating the extension space and leaving the now invalid pointer in the expectations list that is later accessed while removing the expectation. Make sure that helpers are called at the end after all the other extensions are already added. Note that the helper rejection now leaves the mark and labels set, but that's not different from how the NAT was handled before or how the mark and the labels were handled on confirmation failure. And there are no atomicity guarantees provided by the API anyway.

CVSS Vector Analysis

Below is the complete, human-readable breakdown of the CVSS metric string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

▪ Attack Vector (AV): Network
▪ Attack Complexity (AC): Low
▪ Privileges Required (PR): None
▪ User Interaction (UI): None
▪ Scope (S): Unchanged
▪ Confidentiality Impact (C): High
▪ Integrity Impact (I): High
▪ Availability Impact (A): High

Affected Vendors & Systems

Vendor Linux

References & Advisory Links

Metadata Profile

Database Authority

European Union Agency for Cybersecurity (ENISA) EUVD

Assigner

Linux

EPSS Probability

0.62

Known Aliases
CVE-2026-98490 GHSA-4r7h-j2g8-7vfx
Published On

2026-10-18

Last Updated

2026-10-30