{"apiVersion":"1.0","identifier":"CVE-2026-75870","description":"Punk versions before 0.18 for Perl allow session cookie forgery via an empty default HMAC key when a session is declared without a secret. The session keyword freezes its options onto the application as given: it does not require a secret, warn, or refuse to start when one is absent. The cookie read and the write-back both default that key to the empty string, so a declaration with no secret option, or with an undefined or empty one, signs and verifies with a zero-length HMAC-SHA256 key. An attacker who knows the cookie format can then mint one offline carrying any contents the session holds, such as a user identifier or a role. Nothing marks the misconfiguration at runtime: cookies are well formed and sessions round-trip as expected.","publishedAt":"2026-08-22T14:16:33","lastModifiedAt":"2026-08-26T16:51:19","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-75870","cvssScore":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","epssProbability":0.00491,"riskScore":0.95,"affectedProduct":"Punk","affectedVersions":"<0.18","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-75870","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-75870","en":"https://www.redsauce.net/en/cves/CVE-2026-75870","fr":"https://www.redsauce.net/fr/cves/CVE-2026-75870","pt":"https://www.redsauce.net/pt/cves/CVE-2026-75870","de":"https://www.redsauce.net/de/cves/CVE-2026-75870","sk":"https://www.redsauce.net/sk/cves/CVE-2026-75870","el":"https://www.redsauce.net/el/cves/CVE-2026-75870"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-75870"}}