CVE-2026-45186
Description
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.
Statement
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 7.5 | 7.5 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
The typical consequence is CPU consumption, but memory consumption and consumption of other resources can also occur.
Frequently Asked Questions
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