{"id":"CVE-2025-71402","sourceIdentifier":"disclosure@vulncheck.com","published":"2026-08-01T13:16:55.510","lastModified":"2026-10-06T22:10:00.247","vulnStatus":"Deferred","cveTags":[],"descriptions":[{"lang":"en","value":"better-auth versions greater than 1.3.34 and before 1.4.0 contain a vulnerability in the multi-session plugin's /sign-out after-hook, which trusts raw multi-session cookies and forwards extracted values to internalAdapter.deleteSessions without verifying the cookie signature (e.g., via getSignedCookie). An attacker can supply a forged _multi-* cookie to trigger deletion of arbitrary session tokens."},{"lang":"es","value":"Las versiones de better-auth superiores a 1.3.34 y anteriores a 1.4.0 contienen una vulnerabilidad en el after-hook /sign-out del plugin de multi-sesión, que confía en las cookies de multi-sesión sin procesar y reenvía los valores extraídos a internalAdapter.deleteSessions sin verificar la firma de la cookie (p. ej., a través de getSignedCookie). Un atacante puede proporcionar una cookie _multi-* falsificada para activar la eliminación de tokens de sesión arbitrarios."}],"affected":[{"source":"disclosure@vulncheck.com","affectedData":[{"vendor":"better-auth","product":"better-auth","defaultStatus":"unaffected","packageURL":"pkg:npm/better-auth","versions":[{"version":"0","lessThan":"1.4.0","versionType":"semver","status":"affected"},{"version":"1.4.0","versionType":"semver","status":"unaffected"}]}]}],"metrics":{"cvssMetricV40":[{"source":"disclosure@vulncheck.com","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":2.0,"baseSeverity":"LOW","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"HIGH","userInteraction":"PASSIVE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"LOW","subIntegrityImpact":"LOW","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-08-03T19:31:34.482271Z","id":"CVE-2025-71402","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"disclosure@vulncheck.com","type":"Secondary","description":[{"lang":"en","value":"CWE-347"}]}],"references":[{"url":"https://github.com/better-auth/better-auth/security/advisories/GHSA-wmjr-v86c-m9jj","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/better-auth-before-session-revocation-via-forged-cookie","source":"disclosure@vulncheck.com"}]}