Linux Kernel up to 6.6.139/6.12.85/6.18.26/7.0.3 SERVER Message qrtr_ns_worker resource consumption

CVSS Meta Temp Score
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.6.139/6.12.85/6.18.26/7.0.3 and classified as critical. This vulnerability affects the function qrtr_ns_worker of the component SERVER Message Handler. The manipulation results in resource consumption. This vulnerability is known as CVE-2026-43491. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.6.139/6.12.85/6.18.26/7.0.3. Affected is the function qrtr_ns_worker of the component SERVER Message Handler. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: ns: Limit the maximum server registration per node Current code does no bound checking on the number of servers added per node. A malicious client can flood NEW_SERVER messages and exhaust memory. Fix this issue by limiting the maximum number of server registrations to 256 per node. If the NEW_SERVER message is received for an old port, then don't restrict it as it will get replaced. While at it, also rate limit the error messages in the failure path of qrtr_ns_worker(). Note that the limit of 256 is chosen based on the current platform requirements. If requirement changes in the future, this limit can be increased.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-43491 since 05/01/2026. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 315312 (Linux Distros Unpatched Vulnerability : CVE-2026-43491), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.140, 6.12.86, 6.18.27, 7.0.4 or 7.1-rc1 eliminates this vulnerability. Applying the patch e6f6cd501fb54060940a6eb3f4103eeb5e426ae7/3efaad55cad1ded429e3a873bfece389058a526b/35fb4a0c077c5d1049c2628b769e0a1b1e65df0d/868202aa2adae427060a42d5bd663b4d782ec02c/d5ee2ff98322337951c56398e79d51815acbf955 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 (315312). Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

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

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / 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: 315312
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-43491

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.140/6.12.86/6.18.27/7.0.4/7.1-rc1
Patch: e6f6cd501fb54060940a6eb3f4103eeb5e426ae7/3efaad55cad1ded429e3a873bfece389058a526b/35fb4a0c077c5d1049c2628b769e0a1b1e65df0d/868202aa2adae427060a42d5bd663b4d782ec02c/d5ee2ff98322337951c56398e79d51815acbf955

Timelineinfo

05/01/2026 CVE reserved
05/19/2026 +18 days Advisory disclosed
05/19/2026 +0 days VulDB entry created
06/26/2026 +38 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43491 (🔒)
GCVE (CVE): GCVE-0-2026-43491
GCVE (VulDB): GCVE-100-364620

Entryinfo

Created: 05/19/2026 15:29
Updated: 06/26/2026 22:10
Changes: 05/19/2026 15:29 (59), 05/20/2026 05:23 (2), 06/26/2026 22:10 (10)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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