Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-43040

CVE-2026-43040HIGH

Linux Linux — net: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields to zero to prevent an info-leak

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  H  N  H    7.1   .0017    6.4     —

AFFECTED
  Product  Versions                                    Fixed
  Linux    31910575a9de61e78065e93846e8e7a4894a18bf –  —
  Linux    2.6.24 –                                    5.10.253

TIMELINE
  May 1   Reserved by Linux
  May 1   Published (CNA: Linux)
  Oct 15  ENRICHED — CVE-2026-43040 (Linux). Received CVSS 7.1 and CPE data from NVD.

CWE-909 · CNA: Linux · CVSS v3.1 · 11 references · NVD status: Modified

Description

In the Linux kernel, the following vulnerability has been resolved: net: ipv6: ndisc: fix ndisc_ra_useropt to initialize nduseropt_padX fields to zero to prevent an info-leak When processing Router Advertisements with user options the kernel builds an RTM_NEWNDUSEROPT netlink message. The nduseroptmsg struct has three padding fields that are never zeroed and can leak kernel data The fix is simple, just zeroes the padding fields.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
May 1, 2026	Reserved	Reserved by Linux
May 1, 2026	Published	Published (CNA: Linux)
October 15, 2026	ENRICHED	ENRICHED — CVE-2026-43040 (Linux). Received CVSS 7.1 and CPE data from NVD.

Affected

Affected products and packages — 2 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Linux	Linux	—	31910575a9de61e78065e93846e8e7a4894a18bf	—
Linux	Linux	—	2.6.24	5.10.253

Weaknesses

CWE-909

References (11)

Authoritative record: CVE-2026-43040 at cve.org

Vendors: linux

Weaknesses: CWE-909

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-43040 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.