{"answers":{"affected":"5 open source packages ship an affected version, including github.com/nats-io/jwt and github.com/nats-io/nats-server/v2. It affects 2 products.","exploited":"There is no known exploitation of CVE-2020-26521 in the wild and no public exploit code.","fix":"Upgrade github.com/nats-io/jwt to 1.1.0 or later.","what":"CVE-2020-26521 is a high-severity vulnerability in Fedoraproject Fedora, published on 6 Nov 2020. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2020-26521 and fix it if it is affected.\n\nWhat it is: CVE-2020-26521 is a high-severity vulnerability in Fedoraproject Fedora, published on 6 Nov 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2020-26521 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/nats-io/jwt (Go): affected all versions; fixed in 1.1.0\n- github.com/nats-io/jwt (Go): affected all versions; fixed in 1.1.0\n- github.com/nats-io/jwt (Go): affected all versions; fixed in 1.1.0\n- github.com/nats-io/nats-server/v2 (Go): affected all versions; fixed in 2.1.9\n- github.com/nats-io/nats-server/v2 (Go): affected all versions; fixed in 2.1.9\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2020-26521/ (Markdown: https://insights.sbomify.com/CVE-2020-26521/index.md)","id":"CVE-2020-26521","markdown":"https://insights.sbomify.com/CVE-2020-26521/index.md","name":"CVE-2020-26521","record":{"aliases":["DEBIAN-CVE-2020-26521","GHSA-h2fg-54x9-5qhq","GHSA-hmm9-r2m2-qg9w","GO-2022-0402","UBUNTU-CVE-2020-26521"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"NATS server","requires_auth":"none","summary":"A nil dereference in the NATS server JWT library allows attackers to cause a denial of service.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mitre","cpe":[{"product":"fedora","vendor":"fedoraproject"},{"product":"nats-server","vendor":"linuxfoundation"}],"cvss":{"score":7.5,"severity":"high","source":"nvd","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"The JWT library in NATS nats-server before 2.1.9 allows a denial of service (a nil dereference in Go code).","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Nil dereference in NATS JWT, DoS of nats-server","id":"CVE-2020-26521","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":"fedoraproject:fedora","products":["fedoraproject:fedora"],"type":"null_dereference","year":"2020"},"n_packages":5,"n_references":3,"next":{"headline":"Cross-site request forgery in n/a","id":"CVE-2020-26522"},"packages":[{"ecosystem":"Go","fixed":["1.1.0"],"introduced":["0"],"last_affected":[],"package":"github.com/nats-io/jwt","purl":null,"source":"GHSA-h2fg-54x9-5qhq"},{"ecosystem":"Go","fixed":["1.1.0"],"introduced":["0"],"last_affected":[],"package":"github.com/nats-io/jwt","purl":"pkg:golang/github.com/nats-io/jwt","source":"GHSA-h2fg-54x9-5qhq"},{"ecosystem":"Go","fixed":["1.1.0"],"introduced":["0"],"last_affected":[],"package":"github.com/nats-io/jwt","purl":"pkg:golang/github.com/nats-io/jwt","source":"GO-2022-0402"},{"ecosystem":"Go","fixed":["2.1.9"],"introduced":["0"],"last_affected":[],"package":"github.com/nats-io/nats-server/v2","purl":null,"source":"GHSA-hmm9-r2m2-qg9w"},{"ecosystem":"Go","fixed":["2.1.9"],"introduced":["0"],"last_affected":[],"package":"github.com/nats-io/nats-server/v2","purl":"pkg:golang/github.com/nats-io/nats-server/v2","source":"GHSA-hmm9-r2m2-qg9w"}],"prev":{"headline":"Memory corruption in n/a","id":"CVE-2020-26519"},"products":["n/a"],"published":"2020-11-06","related":[{"cvss_score":9.8,"headline":"PHP-CGI OS Command Injection","id":"CVE-2024-4577","kev_date_added":"2024-06-12","published":"2024-06-09"},{"cvss_score":9.8,"headline":"Grafana Authentication Bypass","id":"CVE-2021-39226","kev_date_added":"2022-08-25","published":"2021-10-05"},{"cvss_score":9.8,"headline":"VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow","id":"CVE-2019-5544","kev_date_added":"2021-11-03","published":"2019-12-06"},{"cvss_score":9.6,"headline":"Google Chromium V8 Type Confusion","id":"CVE-2024-4947","kev_date_added":"2024-05-20","published":"2024-05-15"},{"cvss_score":9.6,"headline":"Google Chromium Visuals Use-After-Free","id":"CVE-2024-4671","kev_date_added":"2024-05-13","published":"2024-05-09"},{"cvss_score":9.6,"headline":"Google Chromium Mojo Insufficient Data Validation","id":"CVE-2022-3075","kev_date_added":"2022-09-08","published":"2022-09-26"},{"cvss_score":9.6,"headline":"Google Chromium Indexed DB API Use-After-Free","id":"CVE-2021-30633","kev_date_added":"2021-11-03","published":"2021-10-08"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-04","vendors":["n/a"]},"summary":"A nil dereference in the NATS server JWT library allows attackers to cause a denial of service.","url":"https://insights.sbomify.com/CVE-2020-26521/"}