Arbitrary Code Execution Flaw in Ubuntu's SimpleEval Library
Severity: High (Score: 70.5)
Sources: Linuxsecurity, Ubuntu
Published: · Updated:
Keywords: ubuntu, simpleeval, arbitrary, code, issue, significant, execution
Severity indicators: flaw, issue, arbitrary code execution
Summary
A significant security vulnerability has been identified in the SimpleEval library used in various Ubuntu releases, allowing for arbitrary code execution through specially crafted input. The flaw affects multiple versions of Ubuntu, including 26.04 LTS, 25.10, and earlier LTS versions down to 16.04. Discovered by Byambadalai Sumiya, the vulnerability arises from improper restrictions on attribute access and callback handling within a sandbox environment. Users are advised to update their systems to the latest package versions to mitigate the risk. Affected systems include Ubuntu 26.04 LTS, 25.10, 24.04 LTS, 22.04 LTS, 20.04 LTS, 18.04 LTS, and 16.04 LTS. The vulnerability is critical as it could potentially allow attackers to execute arbitrary code remotely. A standard system update is recommended to apply the necessary patches. The issue has been documented in Ubuntu Security Notice USN-8301-1. Key Points: • A significant vulnerability in SimpleEval allows arbitrary code execution on Ubuntu systems. • The flaw affects multiple Ubuntu versions, including 26.04 LTS and earlier LTS releases. • Users are urged to update their systems to the latest package versions to mitigate risks.
Detailed Analysis
**Impact** All supported Ubuntu releases from 16.04 LTS through 26.04 LTS and their derivatives are affected, potentially impacting millions of systems globally across various sectors using these distributions. The vulnerability allows arbitrary code execution, which could lead to unauthorized system control, data compromise, or disruption of operations. No specific sectors or geographic regions are detailed in the sources. **Technical Details** The flaw arises from improper restriction of attribute access and callback handling within the SimpleEval Python library sandbox, enabling attackers to execute arbitrary code. The vulnerability affects multiple Ubuntu package versions of python3-simpleeval and python-simpleeval. No CVE identifier or malware/tool names are provided. The attack vector involves crafted input to the SimpleEval library, likely during expression evaluation. No IOCs or infrastructure details are mentioned. **Recommended Response** Apply the updated SimpleEval package versions provided for each affected Ubuntu release immediately, prioritizing systems running Ubuntu 26.04 LTS and 25.10. Systems with Ubuntu Pro subscriptions should ensure updates are applied via that service. Monitor for unusual process executions or unexpected code running in environments using SimpleEval. No additional detection signatures or configurations are specified in the available information.
Source articles (2)
- USN-8301-1: SimpleEval vulnerability — Ubuntu · 2026-05-25
Byambadalai Sumiya discovered that SimpleEval did not properly restrict attribute access and callback handling inside a sandbox. An attacker could possibly use this issue to execute arbitrary code. By… - Ubuntu SimpleEval Significant Arbitrary Code Execution Flaw USN-8301 — Linuxsecurity · 2026-05-25
A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 26.04 LTS - Ubuntu 25.10 - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 LTS…
Timeline
- 2026-05-25 — Vulnerability discovered in SimpleEval: Byambadalai Sumiya identified a flaw allowing arbitrary code execution due to improper sandbox restrictions.
- 2026-05-25 — Ubuntu Security Notice USN-8301-1 released: Ubuntu published an advisory detailing the SimpleEval vulnerability and recommended updates for affected systems.
- Recent — Patch availability announced: Ubuntu users are advised to perform a standard system update to apply the necessary patches for SimpleEval.
Related entities
- Ubuntu (Company)
- SimpleEval (Vulnerability)