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CVE Record

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

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

A malicious client may repeatedly register QRTR servers with a Linux node until kernel memory is exhausted, potentially degrading or crashing the system. The issue is a denial-of-service risk; the supplied evidence does not show data theft, code execution, or widespread exploitation.

Executive priority

Treat this as a targeted availability issue requiring prompt verification, especially for embedded, mobile, or specialized Linux deployments using QRTR. Emergency action is not supported by the supplied evidence, but exposed availability-critical systems should receive accelerated patching after compatibility testing.

Technical view

Linux QRTR name-service code lacked a bound on server registrations per node. Repeated NEW_SERVER messages could continually allocate registrations and exhaust memory. The stable fix caps registrations at 256 per node, permits replacement of an existing port, and rate-limits related error messages.

Likely exposure

Exposure is most plausible on affected Linux systems that enable and use QRTR and permit a malicious client to submit name-service registrations. The bundle lists multiple affected kernel versions, but does not fully establish distribution-specific backport status or the access required to reach the interface.

Exploitation context

The supplied record says a malicious client can trigger memory exhaustion. It does not establish whether that client must be local, privileged, or reachable through another component. The CVE is not listed in KEV, and the provided sources report no confirmed active exploitation or public weaponization.

Researcher notes

The security boundary and attacker prerequisites remain insufficiently documented in the bundle. Assessment should focus on QRTR enablement, who can originate NEW_SERVER messages, allocation behavior before the cap, and vendor backport mapping. Avoid inferring remote reachability from the record. The patch's 256-registration ceiling reflects current platform requirements.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable cited stable fix.
  • Check distribution advisories for backported fixes before relying only on kernel version numbers.
  • Where operationally feasible, reduce untrusted client access to systems using QRTR.
  • Prioritize availability-sensitive systems if QRTR is enabled and reachable by less-trusted clients.

Validation and detection

  • Inventory Linux systems and record their running kernel builds and vendor patch status.
  • Determine whether QRTR and its name-service functionality are enabled and operationally required.
  • Confirm the installed kernel includes the relevant stable fix or an equivalent vendor backport.
  • Review affected systems for unexplained memory exhaustion or availability incidents involving QRTR activity.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2026-43491 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
9Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux0c2204a4ad710d95d348ea006f14ba926e842ffd, 0c2204a4ad710d95d348ea006f14ba926e842ffd, 0c2204a4ad710d95d348ea006f14ba926e842ffd, 0c2204a4ad710d95d348ea006f14ba926e842ffd, 0c2204a4ad710d95d348ea006f14ba926e842ffd, 0c2204a4ad710d95d348ea006f14ba926e842ffd, 0c2204a4ad710d95d348ea006f14ba926e842ffd, 0c2204a4ad710d95d348ea006f14ba926e842ffdunaffected
LinuxLinux5.7, 0, 5.10.265, 5.15.216, 6.1.183, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1affected
Weakness

CWE details

No CWE listed

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