{"cve":"CVE-2020-26521","nvd":{"published":"2020-11-06T08:15:13.563","modified":"2026-06-17T03:08:08.270","status":"Modified","description":"The JWT library in NATS nats-server before 2.1.9 allows a denial of service (a nil dereference in Go code).","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-476"],"references":["http://www.openwall.com/lists/oss-security/2020/11/02/2","https://github.com/nats-io/nats-server/commits/master","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VT67XCLIIBYRT762SVFBYFFTQFVSM3SI/","http://www.openwall.com/lists/oss-security/2020/11/02/2","https://github.com/nats-io/nats-server/commits/master"],"products":["fedoraproject:fedora","linuxfoundation:nats-server"],"source":"nvd","synced_at":"2026-10-19T21:11:20.317016139+00:00"},"epss":{"cve":"CVE-2020-26521","score":0.02157,"percentile":0.82188,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-h2fg-54x9-5qhq","url":"https://osv.dev/vulnerability/GHSA-h2fg-54x9-5qhq","summary":"Nil dereference in NATS JWT, DoS of nats-server","modified":"2026-09-10T03:49:12.147242460Z","packages":[{"ecosystem":"Go","name":"github.com/nats-io/jwt","purl":"pkg:golang/github.com/nats-io/jwt","ranges":["<1.1.0"],"fixed":["1.1.0"]}]},{"id":"GHSA-hmm9-r2m2-qg9w","url":"https://osv.dev/vulnerability/GHSA-hmm9-r2m2-qg9w","summary":"Nil dereference in NATS JWT causing DoS of nats-server","modified":"2026-09-10T03:49:14.679744358Z","packages":[{"ecosystem":"Go","name":"github.com/nats-io/nats-server/v2","purl":"pkg:golang/github.com/nats-io/nats-server/v2","ranges":["<2.1.9"],"fixed":["2.1.9"]}]},{"id":"GO-2022-0402","url":"https://osv.dev/vulnerability/GO-2022-0402","summary":"Panic in NATS JWT decoding in github.com/nats-io/jwt","modified":"2026-02-04T03:01:19.864397Z","packages":[{"ecosystem":"Go","name":"github.com/nats-io/jwt","purl":"pkg:golang/github.com/nats-io/jwt","ranges":["<1.1.0"],"fixed":["1.1.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}