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PatchSiren cyber security CVE debrief

CVE-2026-64033 Linux CVE debrief

The Linux kernel has been updated to address a use-after-free vulnerability in the RDMA/rtrs subsystem. The issue arises during the error path of creating path files, where a premature kobject_put() call may lead to srv_path being freed before it is accessed by rtrs_srv_destroy_once_sysfs_root_folders(), resulting in a use-after-free condition. The fix involves reordering the cleanup steps to ensure srv_path remains valid during the helper's access.

Vendor
Linux
Product
Unknown
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-19
Original CVE updated
2026-07-30
Advisory published
2026-07-19
Advisory updated
2026-07-30

Who should care

System administrators and security teams responsible for Linux kernel-based systems, especially those utilizing RDMA/rtrs, should be aware of this vulnerability and apply the necessary patches to prevent potential exploitation.

Technical summary

The vulnerability is located in the RDMA/rtrs subsystem of the Linux kernel. During the error path of rtrs_srv_create_path_files(), kobject_put(&srv_path->kobj) is called before rtrs_srv_destroy_once_sysfs_root_folders(srv_path). This can lead to srv_path being freed prematurely, causing a use-after-free when rtrs_srv_destroy_once_sysfs_root_folders(srv_path) accesses srv_path->srv. The fix reorders these operations to ensure srv_path's validity during access.

Defensive priority

High priority for systems utilizing RDMA/rtrs due to potential for local exploitation.

Recommended defensive actions

  • Apply the official kernel patch to update the RDMA/rtrs subsystem.
  • Review system configurations for RDMA/rtrs usage.
  • Perform vulnerability scanning to identify affected systems.
  • Implement compensating controls to monitor for suspicious activity.
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE record was published on 2026-07-19T16:17:43.493Z and has not been modified since then. The NVD entry is currently Received. Multiple source references are provided, including links to the Linux kernel stable repository.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-64033 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-64033

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-64033 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-64033

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/00904a73272b9f3ef3952fe69a833909dccad1ef

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/01e42aabaf7632beb4bf235c7238b96c746d4144

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/548f3956e53a7f7bde912d8129010b8986d5e602

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/5b74373390113fba798a76b483837029ab010fef

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/92060ab1c5115674cf319175550f85f68405121f

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/b0e9706fb2859064bb6c677554c4d20c713aa8e0

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/eae62c5451e67e8b033c1681fd3b85d7e9a9a28f

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.