{"apiVersion":"1.0","identifier":"CVE-2026-66046","description":"Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic complexity in the storeAtts() function in xmlparse.c, where processing N specified attributes with non-normalized values triggers an O(N^2) linear scan of elementType->defaultAtts to determine CDATA status. A remote unauthenticated attacker can supply a single well-formed XML document of a few megabytes to an application parsing untrusted XML to cause excessive CPU consumption, resulting in denial of service without requiring authentication, external entity resolution, or non-default parser options.","publishedAt":"2026-08-18T15:16:57","lastModifiedAt":"2026-08-20T16:17:40","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-66046","cvssScore":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","epssProbability":0.00391,"riskScore":0.78,"affectedProduct":"Expat","affectedVersions":"<=2.8.3","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-66046","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-66046","en":"https://www.redsauce.net/en/cves/CVE-2026-66046","fr":"https://www.redsauce.net/fr/cves/CVE-2026-66046","pt":"https://www.redsauce.net/pt/cves/CVE-2026-66046","de":"https://www.redsauce.net/de/cves/CVE-2026-66046","sk":"https://www.redsauce.net/sk/cves/CVE-2026-66046","el":"https://www.redsauce.net/el/cves/CVE-2026-66046"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-66046"}}