CVE-2026-33258

OVERVIEW CVE-2026-33258 is a denial-of-service vulnerability affecting DNS systems that implement NSEC and NSEC3 caching mechanisms. An attacker can exploit this flaw by publishing and querying a specially crafted DNS zone to trigger excessive memory allocation in the negative and aggressive cache structures, potentially degrading DNS resolver performance. SEVERITY The vulnerability carries a CVSS score of 5.3 (Medium) with a network-based attack vector requiring no authentication or user interaction. The attack has low complexity and results in availability impact without affecting confidentiality or integrity. The relatively low EPSS score of 0.000030 indicates this vulnerability ranks lower than approximately 99.99% of all CVEs in terms of exploitation likelihood. EXPLOITATION STATUS There is no current evidence of active exploitation. The vulnerability is not listed on the Known Exploited Vulnerabilities catalog and remains inactive on threat intelligence hotlists. The lack of readily available exploit code and minimal community attention suggest this remains a theoretical vulnerability with limited real-world threat activity at this time.