CVE-2021-33624 Information disclosure in n/a

What is CVE-2021-33624?

CVE-2021-33624 is a medium-severity vulnerability in Debian Debian Linux, published on 23 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In kernel/bpf/verifier.c in the Linux kernel before 5.12.13, a branch can be mispredicted (e.g., because of type confusion) and consequently an unprivileged BPF program can read arbitrary memory locations via a side-channel attack, aka CID-9183671af6db.

Weakness: CWE-843

Which versions are affected by CVE-2021-33624?

It affects 2 products.

Products include Debian Debian Linux, Linux kernel.

How do I fix CVE-2021-33624?

Apply the vendor's patch.

Is CVE-2021-33624 being exploited?

There is no known exploitation of CVE-2021-33624 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

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 A-192972537, AZL-6564, DEBIAN-CVE-2021-33624, GHSA-w9w3-f8q7-x576, PUB-A-192972537, UBUNTU-CVE-2021-33624.