{"id":"AZL-81242","summary":"CVE-2026-21713 affecting package nodejs for versions less than 20.14.0-15","details":"A flaw in Node.js HMAC verification uses a non-constant-time comparison when validating user-provided signatures, potentially leaking timing information proportional to the number of matching bytes. Under certain threat models where high-resolution timing measurements are possible, this behavior could be exploited as a timing oracle to infer HMAC values.\r\n\r\nNode.js already provides timing-safe comparison primitives used elsewhere in the codebase, indicating this is an oversight rather than an intentional design decision.\r\n\r\nThis vulnerability affects **20.x, 22.x, 24.x, and 25.x**.","modified":"2026-08-28T17:47:34.099775320Z","published":"2026-03-30T20:16:19Z","upstream":["CVE-2026-21713"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-21713"}],"affected":[{"package":{"name":"nodejs","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/nodejs"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"20.14.0-15"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-81242.json"}}],"schema_version":"1.9.0"}