CVE-2021-3696MediumCVSS 4.5
A heap out-of-bounds write may heppen during the handling of Huffman tables in the PNG reader. This may lead to data corruption in the heap space. Confidentiality Integrity and Availablity impact may be considered Low as it's very complex to an attacker control the encoding and positioning of corrupted Huffman entries to achieve results such as arbitrary code execution and/or secure boot circumvention. This flaw affects grub2 versions prior grub-2.12.
🔗 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
- azl3 grub2 2.06-14 on Azure Linux 3.0
- azl3 grub2 2.06-23 on Azure Linux 3.0
✅ Remediation
KBCBL-Mariner Releases (Security Update) — fixed build 2.06-14