CVE-2021-26910 Race condition in n/a

What is CVE-2021-26910?

CVE-2021-26910 is a high-severity vulnerability in Debian Debian Linux, published on 8 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

Firejail before 0.9.64.4 allows attackers to bypass intended access restrictions because there is a TOCTOU race condition between a stat operation and an OverlayFS mount operation.

Weakness: CWE-367

Which versions are affected by CVE-2021-26910?

It affects 2 products.

Products include Debian Debian Linux, Firejail Project Firejail.

How do I fix CVE-2021-26910?

Upgrade to a fixed version.

Is CVE-2021-26910 being exploited?

There is no known exploitation of CVE-2021-26910 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 DEBIAN-CVE-2021-26910, DLA-2554-1, DSA-4849-1, GHSA-2q4h-h5jp-942w, MGASA-2021-0120, UBUNTU-CVE-2021-26910 and 1 more.