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CVE-2026-26933: CVE-2026-26933: Improper Validation of Array Index in Elastic Packetbeat Leading to Denial of Service

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CVE-2026-26933: Improper Validation of Array Index in Elastic Packetbeat Leading to Denial of Service

Vulnerability ID: CVE-2026-26933
CVSS Score: 5.7
Published: 2026-03-19

CVE-2026-26933 is a medium-severity Denial of Service (DoS) vulnerability in Elastic Packetbeat caused by improper validation of array indices within the Linux procfs and PostgreSQL protocol parsers. Exploitation allows an attacker on an adjacent network to crash the monitoring agent via malformed network traffic, creating a blind spot in network security telemetry.

TL;DR

A flaw in Elastic Packetbeat protocol parsers (CWE-129) allows adjacent attackers to trigger out-of-bounds reads and infinite loops, causing process panics and denial of service. Patches are available in versions 8.19.11 and 9.2.5.

⚠️ Exploit Status: POC

Technical Details

  • CWE ID: CWE-129
  • Attack Vector: Adjacent Network
  • CVSS Score: 5.7
  • Impact: Denial of Service (Crash/Hang)
  • Exploit Status: Proof of Concept
  • CISA KEV: False

Affected Systems

  • Elastic Packetbeat
  • Elastic Packetbeat: 8.0.0 <= v <= 8.19.10 (Fixed in: 8.19.11)
  • Elastic Packetbeat: 9.0.0 <= v <= 9.2.4 (Fixed in: 9.2.5)

Code Analysis

Commit: 9410984

Initial fix commit for Linux procfs parser out-of-bounds slicing vulnerability.

Commit: dec1b31

Second fix commit addressing PostgreSQL parser infinite loop and data row boundary validation.

Mitigation Strategies

  • Upgrade Elastic Packetbeat to versions 8.19.11 or 9.2.5 to implement comprehensive input validation.
  • Implement network segmentation to ensure Packetbeat interfaces only monitor trusted network segments.
  • Deploy upstream traffic sanitization to drop malformed PostgreSQL traffic before it reaches monitoring nodes.
  • Configure automated alerting for frequent packetbeat service restarts and Go runtime panic logs.

Remediation Steps:

  1. Identify all deployed instances of Elastic Packetbeat within the environment.
  2. Verify the running version of Packetbeat using the command line (packetbeat version).
  3. Download the updated binary (8.19.11 or 9.2.5) from the official Elastic repository.
  4. Stop the running Packetbeat service.
  5. Replace the vulnerable binary with the updated version and restart the service.
  6. Monitor system logs for the first 24 hours to ensure stable operation and absence of runtime panics.

References

Read the full report for CVE-2026-26933 on our website for more details including interactive diagrams and full exploit analysis.

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