Vulnerabilities in Expat Affect XML-RPC and Ayttm Packages

Severity: Medium (Score: 57.8)

Sources: Ubuntu

Published: 2026-05-27 · Updated: 2026-05-27

Keywords: discovered, expat, ayttm, vulnerabilities, xml-rpc, vendored, incorrectly

Severity indicators: vulnerabilities

Summary

Two vulnerabilities have been identified in the Expat library, which is included in both XML-RPC for C and C++ and Ayttm. These vulnerabilities allow attackers to potentially execute arbitrary code or cause a crash by improperly handling certain files. Affected systems include those using the vulnerable versions of these packages. Users are advised to perform standard system updates to mitigate these issues. The vulnerabilities are significant due to the potential for remote code execution. No specific CVEs were mentioned in the articles, but the vulnerabilities are critical enough to warrant immediate attention from system administrators. Ubuntu Pro offers security coverage for affected packages, highlighting the importance of maintaining updated systems. Key Points: • Expat vulnerabilities in XML-RPC and Ayttm could allow remote code execution. • Affected systems require immediate updates to mitigate potential attacks. • Standard system updates are recommended to address these vulnerabilities.

Detailed Analysis

**Impact** Systems using the Expat library vendored within XML-RPC for C/C++ and Ayttm packages are affected. An attacker could exploit these vulnerabilities to cause application crashes or execute arbitrary code, potentially impacting any organization relying on these packages. The scope includes users of Ubuntu distributions where these packages are deployed; no specific sectors, geographies, or data types at risk are detailed in the sources. **Technical Details** The vulnerabilities arise from improper handling of certain files by the Expat library embedded in XML-RPC and Ayttm. Exploitation could lead to denial of service or remote code execution. No CVE identifiers, malware, tools, or infrastructure details are provided. The attack vector involves crafted files processed by the vulnerable packages. No indicators of compromise (IOCs) or kill chain stages are specified. **Recommended Response** Apply the latest system updates that include patched versions of the affected XML-RPC and Ayttm packages immediately. Ensure all systems running these packages are updated to the versions specified by Ubuntu security notices USN-8313-1 and USN-8314-1. Monitor for unusual crashes or execution behavior related to these applications. No additional detection signatures or configuration changes are detailed in the advisories.

Source articles (2)

• USN-8313-1: XML-RPC for C and C++ vulnerabilities — Ubuntu · 2026-05-27
  It was discovered that Expat, vendored in XML-RPC, incorrectly handled certain files. An attacker could possibly use this issue to cause a crash or execute arbitrary code. It was discovered that Expat…
• USN-8314-1: Ayttm vulnerabilities — Ubuntu · 2026-05-27
  It was discovered that Expat, vendored in Ayttm, incorrectly handled certain files. An attacker could possibly use this issue to cause a crash or execute arbitrary code. It was discovered that Expat,…

Timeline

• 2026-05-27 — Vulnerabilities announced for XML-RPC: Expat in XML-RPC was found to improperly handle files, allowing potential crashes or code execution.
• 2026-05-27 — Vulnerabilities announced for Ayttm: Expat in Ayttm was similarly found to have vulnerabilities that could lead to crashes or arbitrary code execution.

Related entities

• Zero-day Exploit (Attack Type)
• CWE-94 - Code Injection (Cwe)
• Ubuntu (Company)