Linux Kernel up to 6.19.11 ndisc_ra_useropt nduseropt_padX memory leak

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CTI Interest Score
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6.3$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.19.11. Affected by this issue is the function ndisc_ra_useropt. Performing a manipulation of the argument nduseropt_padX results in memory leak. This vulnerability is cataloged as CVE-2026-43040. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.19.11. This affects the function ndisc_ra_useropt. The manipulation of the argument nduseropt_padX with an unknown input leads to a memory leak vulnerability. CWE is classifying the issue as CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. This is going to have an impact on availability. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-43040 since 05/01/2026. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 321588 (SUSE SLES16 Security Update : kernel (SUSE-SU-2026:22127-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22 or 6.19.12 eliminates this vulnerability. Applying the patch 1da9023f6b071a38e5430ffbce4b70b2b1ac4f9c/2fe4d0ba690a69ad6ae9f7ab9bdc96e02610b648/11d7fe97421cfc81549940c20ed5ac9472d6db05/7f56d87e527bb5a13c3e8b0d5840cb6332822f6d/4f810c686fde509d1cdaa706322d9d2531f8f1a4/b485eef3d97b7aae55ce669b6de555ec81f3d21c/ef3645606e4a635d5062a492f22b7f490852ee67/ae05340ccaa9d347fe85415609e075545bec589f is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (321588). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.1
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 321588
Nessus Name: SUSE SLES16 Security Update : kernel (SUSE-SU-2026:22127-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.253/5.15.203/6.1.168/6.6.134/6.12.81/6.18.22/6.19.12
Patch: 1da9023f6b071a38e5430ffbce4b70b2b1ac4f9c/2fe4d0ba690a69ad6ae9f7ab9bdc96e02610b648/11d7fe97421cfc81549940c20ed5ac9472d6db05/7f56d87e527bb5a13c3e8b0d5840cb6332822f6d/4f810c686fde509d1cdaa706322d9d2531f8f1a4/b485eef3d97b7aae55ce669b6de555ec81f3d21c/ef3645606e4a635d5062a492f22b7f490852ee67/ae05340ccaa9d347fe85415609e075545bec589f

Timelineinfo

05/01/2026 Advisory disclosed
05/01/2026 +0 days CVE reserved
05/01/2026 +0 days VulDB entry created
07/17/2026 +77 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43040 (🔒)
GCVE (CVE): GCVE-0-2026-43040
GCVE (VulDB): GCVE-100-360669

Entryinfo

Created: 05/01/2026 17:53
Updated: 07/17/2026 11:18
Changes: 05/01/2026 17:53 (59), 06/20/2026 21:47 (2), 07/17/2026 11:18 (11)
Complete: 🔍
Cache ID: 216::103

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