CVE-2021-20257MediumCVSS 6.5

An infinite loop flaw was found in the e1000 NIC emulator of the QEMU. This issue occurs while processing transmits (tx) descriptors in process_tx_desc if various descriptor fields are initialized with invalid values. This flaw allows a guest to consume CPU cycles on the host resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Published
March 10, 2023
Last Modified
—

🔗 CVE IDs covered (1)

📋 Description

Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability? One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.

🎯 Affected products2

  • cbl2 qemu 6.2.0-2 on CBL Mariner 2.0
  • cm1 qemu-kvm 4.2.0-39 on CBL Mariner 1.0

✅ Remediation

KBCBL-Mariner Releases (Security Update) — fixed build 4.2.0-39 KBCBL-Mariner Releases (Security Update) — fixed build 6.2.0-2

🔗 References (2)