Ubuntu’s Rust Transition and the sudo-rs Security Vulnerabilities: A Technical Analysis

Ubuntu’s effort to modernize its system stack by rewriting critical components in Rust has been one of the most significant architectural changes in recent years. As part of this transition, Canonical introduced sudo-rs, a Rust-based reimplementation of the traditional sudo command. While the goal is to enhance safety and long-term maintainability, recent security issues in sudo-rs show that such transitions are not without challenges. This article dives into the technical background of Ubuntu’s Rust migration, the vulnerabilities discovered in sudo-rs, and what these findings mean for the wider ecosystem.

The Motivation Behind Rust in Ubuntu Rust has gained popularity as a systems programming language primarily because of its strong memory-safety guarantees. Ubuntu’s ongoing goal is to reduce the risk of memory-related vulnerabilities by rewriting critical system utilities in Rust. By adopting Rust, Ubuntu aims to achieve:

• Prevention of memory corruption issues such as buffer overflows.
• Reduction in privilege escalation vulnerabilities.
• Long-term maintainability through safer abstractions.

The introduction of sudo-rs fits directly into this strategy.

Security Issues Discovered in sudo-rs In 2025, several significant vulnerabilities were identified in sudo-rs. While none of them were memory-safety violations, they still posed noteworthy security risks. 1. Password Input Echo Issue A flaw was found in which partially entered password characters could be echoed back to the terminal if a timeout occurred during password entry. This was not a memory bug but a terminal state management error. Root cause:

• Incorrect handling of terminal echo control during timeouts.
• A logic bug rather than a memory-safety problem.

2. Timestamp Authentication Mismatch When configurations such as Defaults targetpw or Defaults rootpw were enabled, sudo-rs incorrectly associated timestamp authentication records with the wrong user. Impact:

• A user might bypass authentication by exploiting cached credentials.

This posed a potential privilege boundary issue. 3. Information Disclosure Vulnerabilities (CVE-2025–46717 and CVE-2025–46718) Two lower-severity CVEs were identified:

• Users with restricted sudo permissions could determine whether certain file paths existed.
• Users could list sudoers permissions of other accounts using the -U flag.

These were not privilege escalation vulnerabilities but enabled unauthorized information gathering.

What These Issues Reveal Despite misconceptions, Rust does not eliminate all classes of bugs. It specifically prevents memory-safety errors but does not protect against:

• Logic bugs
• Incorrect state handling
• Feature parity mismatches between rewritten tools and their original versions

The vulnerabilities in sudo-rs highlight that:

• Complex system utilities carry intricate behavior expectations.
• Rewriting decades-old tools requires extremely thorough behavioral testing.
• Rust ensures memory safety, but correctness still relies on rigorous engineering.

Canonical’s Response and Patches Canonical responded rapidly by issuing a security notice and updating sudo-rs to version 0.2.8–1ubuntu5.2. The patches corrected all known issues, and upstream maintainers also addressed the logic bugs. This quick patch cycle indicates that the Rust transition is being actively monitored and supported.

Is the Rust Transition Still the Right Direction? Even with these issues, the answer is still yes. Long-term advantages:

• Strong protection against memory-based vulnerabilities.
• More sustainable and safer system tooling.
• Reduced attack surface over time.

Short-term drawbacks:

• Early-stage projects are more prone to logic bugs.
• Behavioral equivalence takes time to perfect.
• Rewrites need extensive security auditing.

The vulnerabilities do not imply Rust is failing. Instead, they demonstrate the natural growing pains of replacing mature tools with new implementations.

Conclusion Ubuntu’s move toward Rust-based system utilities is a forward-looking strategy designed to increase safety and robustness. The vulnerabilities discovered in sudo-rs were:

• Logic errors, not memory safety violations,
• Quickly patched,
• Valuable indicators of where further testing is required.

As the ecosystem matures, tools like sudo-rs will become more reliable and secure. This milestone is simply part of the broader evolution of Linux system infrastructure.

Read the full article here: https://kurtulusoz.medium.com/ubuntus-rust-transition-and-the-sudo-rs-security-vulnerabilities-a-technical-analysis-da80e96734cd