CVE-2021-29155 Information disclosure in n/a

What is CVE-2021-29155?

CVE-2021-29155 is a medium-severity vulnerability in Debian Debian Linux, published on 20 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of pointer arithmetic operations, the pointer modification performed by the first operation is not correctly accounted for when restricting subsequent operations.

Weakness: CWE-125

Which versions are affected by CVE-2021-29155?

It affects 3 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Linux kernel.

How do I fix CVE-2021-29155?

Apply the vendor's patch.

Is CVE-2021-29155 being exploited?

There is no known exploitation of CVE-2021-29155 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-186337918, AZL-6545, DEBIAN-CVE-2021-29155, GHSA-4x89-mjpg-vp94, PUB-A-186337918, UBUNTU-CVE-2021-29155.