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Microsoft Security Response CenterCVE-2026-6409

Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted input

High 1 CVE Published Apr 23, 2026 at 1:11 AM UTC

Summary

Mariner

Products covered

  • azl3 mysql 8.0.45-2 on Azure Linux 3.0

  • cbl2 protobuf 3.17.3-5 on CBL Mariner 2.0

  • azl3 pytorch 2.2.2-12 on Azure Linux 3.0

  • azl3 protobuf 25.3-6 on Azure Linux 3.0

  • cbl2 protobuf 3.17.3-5 on CBL-Mariner 2.0

Remediation

CBL-Mariner Releases Release Notes

Vendor-listed fixes

  • 25.3-7

CVEs in this advisory 1

Update history

What changed in later vendor updates

SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.

    • Added affected products: cbl2 protobuf 3.17.3-5 on CBL-Mariner 2.0.
    • The vendor changed its remediation guidance.

Updates

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Updated by Microsoft Security Response Center

    The vendor changed the advisory after it was first published.

  3. Added to SecurityAlert

    We collected the advisory from the official source.

  4. Confirmed at the source

    Our collector saw this advisory during a later source check.