CVE-2021-3506 Information disclosure in kernel

What is CVE-2021-3506?

CVE-2021-3506 is a high-severity vulnerability in Debian Debian Linux, published on 19 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

An out-of-bounds (OOB) memory access flaw was found in fs/f2fs/node.c in the f2fs module in the Linux kernel in versions before 5.12.0-rc4. A bounds check failure allows a local attacker to gain access to out-of-bounds memory leading to a system crash or a leak of internal kernel information. The highest threat from this vulnerability is to system availability.

Weakness: CWE-125

Which versions are affected by CVE-2021-3506?

It affects 12 products.

Products include Debian Debian Linux, Linux kernel, Netapp Cloud Backup, Netapp H300e Firmware, Netapp H300s Firmware, Netapp H410c Firmware and 6 more.

How do I fix CVE-2021-3506?

Upgrade to a fixed version.

Is CVE-2021-3506 being exploited?

There is no known exploitation of CVE-2021-3506 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-6571, DEBIAN-CVE-2021-3506, GHSA-63rg-3wjj-wxhg, UBUNTU-CVE-2021-3506.