{"id":"CVE-2026-48525","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-48525","generatedAt":"2026-10-28T04:45:42.613Z","title":"In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid.","description":"PyJWT is a JSON Web Token implementation in Python. From 2.8.0 to 2.12.1, when verifying detached JWS tokens using the unencoded-payload option (\"b64\": false, RFC 7797), PyJWT performs Base64URL decoding of the compact-serialization payload segment before enforcing the detached-payload rules. For b64=false, PyJWT later discards that decoded payload and replaces it with the caller-provided detached_payload. In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid. This creates an unauthenticated DoS vector against any endpoint that verifies detached JWS using PyJWT. This vulnerability is fixed in 2.13.0.","published":"2026-05-28T16:16:30.000Z","lastModified":"2026-10-25T23:10:00.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"cwe":["CWE-400"],"affected":["pyjwt project/pyjwt"],"epss":{"score":0.0037,"percentile":0.3078,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.37%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/jpadilla/pyjwt/security/advisories/GHSA-w7vc-732c-9m39","tags":["Exploit","Mitigation","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/jpadilla/pyjwt/security/advisories/GHSA-w7vc-732c-9m39","tags":["Exploit","Mitigation","Vendor Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-48525","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}