CVE-2021-3156 is a high-severity vulnerability affecting Sudo, a widely used utility in many systems. This vulnerability, caused by an off-by-one error, can lead to a heap-based buffer overflow, allowing attackers to escalate their privileges to root level. It impacts a range of systems, including various versions of Sudo, Fedora, Debian Linux, and others. To protect against this vulnerability, it's essential to update to Sudo version 1.9.5p2 or apply relevant security updates provided by system vendors.

How do I know if I'm affected?

If you're wondering whether you're affected by the vulnerability, you'll need to check if you're using a version of Sudo within the affected range. This includes legacy versions from 1.8.2 to 1.8.31p2 and stable versions from 1.9.0 to 1.9.5p1. For Apple users, the vulnerability affects macOS Big Sur 11.2, macOS Catalina 10.15.7, and macOS Mojave 10.14.6. A local attacker could exploit this vulnerability to elevate their privileges. To stay safe, ensure you have the latest security updates installed on your system.

What should I do if I'm affected?

If you're affected by the vulnerability, update your system immediately. For Sudo, upgrade to version 1.9.5p2. Fedora 32 users can run the command su -c 'dnf upgrade --advisory FEDORA-2021-8840cbdccd'. Apple users should install the latest security updates for macOS Big Sur 11.2.1, macOS Catalina 10.15.7, and macOS Mojave 10.14.6. Always keep your system updated to stay protected.

Is this in CISA’s Known Exploited Vulnerabilities Catalog?

Yes, CVE-2021-3156 is included in CISA's Known Exploited Vulnerabilities Catalog. This high-severity vulnerability, known as a heap-based buffer overflow in Sudo, allows attackers to escalate their privileges to root level. It was added to the catalog on April 6, 2022, with a due date of April 27, 2022. To address this vulnerability, apply updates as per vendor instructions.

Weakness enumeration

The weakness enumeration for this vulnerability is categorized as CWE-193, which is due to an off-by-one error. This error can lead to a heap-based buffer overflow, allowing attackers to escalate their privileges.

For more details

CVE-2021-3156 is a high-severity vulnerability that affects numerous systems and software configurations. To better understand its description, severity, technical details, and known affected software configurations, you can refer to the NVD page or the links below.

• Sudo Heap-Based Buffer Overflow

• Cisco Security Advisory

• Fedora 32 Update: sudo-1.9.5p2-1.fc32

• APPLE-SA-2021-02-09-1 macOS Updates