{"id":"UBUNTU-CVE-2020-26521","details":"The JWT library in NATS nats-server before 2.1.9 allows a denial of service (a nil dereference in Go code).","modified":"2026-05-20T16:04:20.477131916Z","published":"2020-11-06T08:15:00Z","upstream":["CVE-2020-26521"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2020-26521"},{"type":"REPORT","url":"https://advisories.nats.io/CVE/CVE-2020-26521.txt"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2020-26521"},{"type":"REPORT","url":"https://github.com/nats-io/jwt/security/advisories/GHSA-h2fg-54x9-5qhq"},{"type":"REPORT","url":"http://www.openwall.com/lists/oss-security/2020/11/02/2"}],"affected":[{"package":{"name":"golang-github-nats-io-jwt","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/golang-github-nats-io-jwt?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.0~git20181120.285cf2c-4"],"ecosystem_specific":{"binaries":[{"binary_name":"golang-github-nats-io-jwt-dev","binary_version":"0.0~git20181120.285cf2c-4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-26521.json"}},{"package":{"name":"golang-github-nats-io-jwt","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/golang-github-nats-io-jwt?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.0~git20181120.285cf2c-4.1"],"ecosystem_specific":{"binaries":[{"binary_name":"golang-github-nats-io-jwt-dev","binary_version":"0.0~git20181120.285cf2c-4.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-26521.json"}},{"package":{"name":"golang-github-nats-io-jwt","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/golang-github-nats-io-jwt?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.1-1","2.5.2-1","2.5.2-2"],"ecosystem_specific":{"binaries":[{"binary_version":"2.5.2-2","binary_name":"golang-github-nats-io-jwt-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-26521.json"}},{"package":{"name":"golang-github-nats-io-jwt","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/golang-github-nats-io-jwt?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.7.3-1"],"ecosystem_specific":{"binaries":[{"binary_name":"golang-github-nats-io-jwt-dev","binary_version":"2.7.3-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-26521.json"}},{"package":{"name":"golang-github-nats-io-jwt","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/golang-github-nats-io-jwt?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.7.3-1","2.8.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"golang-github-nats-io-jwt-dev","binary_version":"2.8.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-26521.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}