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NVD / CVE Program· CNA Linux

CVE-2026-43491: net: qrtr: ns: Limit the maximum server registration per node

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.14% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 35fb4a0c077c5d1049c2628b769e0a1b1e65df0d, 3efaad55cad1ded429e3a873bfece389058a526b, 868202aa2adae427060a42d5bd663b4d782ec02c; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1.

Low priority for now. Upgrade to Linux Linux 35fb4a0c077c5d1049c2628b769e0a1b1e65df0d, 3efaad55cad1ded429e3a873bfece389058a526b, 868202aa2adae427060a42d5bd663b4d782ec02c; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 19, 2026
Updated
Nov 6, 2026
EPSS
0.1% · 4th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-43491

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.7 and later · before 6.6.140
  • linux linux kernel6.7 and later · before 6.12.86
  • linux linux kernel6.13 and later · before 6.18.27
  • linux linux kernel6.19 and later · before 7.0.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.7affected
    • 0c2204a4ad710d95d348ea006f14ba926e842ffd and later · before b48fc702b20233b809f01053232c3cd5083c97b4affected · git
    • 0c2204a4ad710d95d348ea006f14ba926e842ffd and later · before 991c431077b19176d3fe3bb54054c063776a8cdcaffected · git
    • 0c2204a4ad710d95d348ea006f14ba926e842ffd and later · before 94914731ca0b99899dceadd80d2df00584a688caaffected · git
    • 0c2204a4ad710d95d348ea006f14ba926e842ffd and later · before e6f6cd501fb54060940a6eb3f4103eeb5e426ae7affected · git
    • 0c2204a4ad710d95d348ea006f14ba926e842ffd and later · before 3efaad55cad1ded429e3a873bfece389058a526baffected · git
    • 0c2204a4ad710d95d348ea006f14ba926e842ffd and later · before 35fb4a0c077c5d1049c2628b769e0a1b1e65df0daffected · git
    • 0c2204a4ad710d95d348ea006f14ba926e842ffd and later · before 868202aa2adae427060a42d5bd663b4d782ec02caffected · git
    • 0c2204a4ad710d95d348ea006f14ba926e842ffd and later · before d5ee2ff98322337951c56398e79d51815acbf955affected · git
    • before 5.7not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:13linuxbefore 6.12.86-16.12.86-1
Debian:14linuxbefore 7.0.4-17.0.4-1
openSUSE:Tumbleweedkernel-sourcebefore 7.0.10-1.17.0.10-1.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-43490May 15, 2026 · ksmbd: validate inherited ACE SID length
    35Monitor
  • ← EarlierCVE-2026-46333May 15, 2026 · ptrace: slightly saner 'get_dumpable()' logic
    40Plan
  • Later →CVE-2026-43492May 19, 2026 · lib/crypto: mpi: Fix integer underflow in mpi_read_raw_from_sgl()
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux35fb4a0c077c5d1049c2628b769e0a1b1e65df0dVendor (CNA)
Linux Linux3efaad55cad1ded429e3a873bfece389058a526bVendor (CNA)
Linux Linux868202aa2adae427060a42d5bd663b4d782ec02cVendor (CNA)
Linux Linux94914731ca0b99899dceadd80d2df00584a688caVendor (CNA)
Linux Linux991c431077b19176d3fe3bb54054c063776a8cdcVendor (CNA)
Linux Linuxb48fc702b20233b809f01053232c3cd5083c97b4Vendor (CNA)
Linux Linuxd5ee2ff98322337951c56398e79d51815acbf955Vendor (CNA)
Linux Linuxe6f6cd501fb54060940a6eb3f4103eeb5e426ae7Vendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.06.6.141.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
opensuse:kernel-source7.0.10-1.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records