CVE-2026-0992 is a vulnerability identified in the libxml2 library, a widely used XML parsing library integrated into Red Hat Enterprise Linux 10. The flaw arises from the way libxml2 processes XML catalogs that contain repeated <nextCatalog> elements pointing repeatedly to the same downstream catalog. This causes the XML parser to redundantly traverse catalog chains multiple times, leading to uncontrolled resource consumption, specifically excessive CPU usage. The vulnerability can be triggered remotely by supplying crafted XML catalogs, which causes the parser to enter a loop or repeated processing cycle, degrading application availability and potentially causing denial-of-service conditions. The CVSS 3.1 base score is 2.9, reflecting a low severity primarily because the attack vector is local, the attack complexity is high, and no privileges or user interaction are required. The vulnerability impacts the availability of applications relying on libxml2 for XML catalog processing but does not affect confidentiality or integrity. No known exploits have been reported in the wild, and no patches or mitigations have been officially released at the time of publication. The vulnerability highlights the importance of validating and limiting XML catalog inputs to prevent resource exhaustion attacks in XML parsing components.

The primary impact of CVE-2026-0992 is a denial-of-service condition caused by excessive CPU consumption during XML catalog processing. Organizations using Red Hat Enterprise Linux 10 with libxml2 in environments where XML catalogs are processed—such as middleware, enterprise applications, or services that parse XML configurations—may experience degraded application availability or service interruptions. While the vulnerability does not compromise data confidentiality or integrity, the availability impact can disrupt business operations, especially in critical systems relying on XML parsing for configuration or data exchange. The attack requires local access and has high complexity, limiting widespread exploitation. However, in multi-tenant or shared environments where untrusted XML input might be processed, this vulnerability could be leveraged by malicious insiders or compromised accounts to degrade service performance. The lack of known exploits and patches reduces immediate risk but does not eliminate the need for proactive mitigation.

To mitigate CVE-2026-0992, organizations should implement the following specific measures: 1) Apply any forthcoming patches or updates from Red Hat or libxml2 maintainers promptly once available. 2) Restrict and validate XML catalog inputs rigorously to prevent processing of crafted catalogs containing repeated <nextCatalog> elements. 3) Implement resource limits on processes handling XML parsing, such as CPU time quotas or process isolation, to contain potential resource exhaustion. 4) Monitor system and application logs for unusual CPU spikes or repeated XML catalog processing patterns indicative of exploitation attempts. 5) Where possible, disable or limit XML catalog processing features if not required by the application. 6) Employ application-layer filtering or input sanitization to detect and block malicious XML inputs before they reach the parser. 7) Conduct security reviews of XML processing workflows to identify and remediate other potential resource consumption vulnerabilities. These targeted mitigations go beyond generic advice by focusing on input validation, resource control, and monitoring specific to XML catalog processing.