Junglewise Threat Intelligence

CVE-2026-43125: Linux Kernel buffer overflow in dlm_search_rsb_tree

CVE-2026-43125 · Severity: critical · CVSS 9.8 · Published 2026-05-06

Technologies: Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9, Linux Kernel. Vendors: Red Hat, Linux.

Executive brief

A vulnerability exists in the Linux kernel's Distributed Lock Manager (DLM), a component used to coordinate resources in clustered environments. An attacker can send a specially crafted network message that triggers a memory error, potentially allowing them to crash the system or execute unauthorized commands. This could lead to a complete loss of system availability and the exposure of sensitive data across the cluster.

Technical details

This vulnerability is classified as an out-of-bounds write (CWE-787) and improper handling of length parameter (CWE-130) within the Linux kernel's Distributed Lock Manager (DLM) subsystem. The root cause is located in the `dlm_search_rsb_tree()` function in `fs/dlm/lock.c`, where a `len` parameter derived from unvalidated network messages is used in a `memcpy()` operation into a fixed-size buffer (`key[DLM_RESNAME_MAXLEN]`). If the provided length exceeds `DLM_RESNAME_MAXLEN`, a stack-based buffer overflow occurs. The attack vector is over the network, requiring no prior authentication or user interaction. Successful exploitation can result in a kernel panic (DoS) or arbitrary code execution with kernel privileges. Patches have been released for various stable kernel branches and Red Hat Enterprise Linux versions.

Affected products

  • Linux Linux Kernel 7210cb7a72a22303cdb225bd1aea28697a17bbae to 67288113c5e6cf9e659b4065c0ed6f16100e0c71
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9

Timeline

  • 2026-01-20: other: Initial patch authored
  • 2026-05-06: advisory: CVE published
  • 2026-06-10: patched: Red Hat security advisory issued

References

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