CVE-2026-45186

A flaw was found in libexpat. When processing a specially crafted XML input containing a specific pattern of attributes, the parsing time increases quadratically due to checks for attribute name collisions. This consumes excessive CPU resources and eventually results in a denial of service.

To exploit this issue, an attacker needs to be able to process a specially crafted XML file or input with an application linked to the libexpat library. Also, the only security impact of this flaw is a high consumption of CPU resources that can eventually cause a denial of service. Due to this reason, this vulnerability has been rated with an important severity.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this vulnerability, restrict the maximum size of incoming XML payloads. It is especially critical to limit the decompressed size if the application accepts compressed XML files. Also, consider running the application inside a container or a restricted environment to ensure that the high consumption of CPU resources does not affect the host system.