{"cve":"CVE-2021-42697","nvd":{"published":"2021-11-02T22:15:08.957","modified":"2026-06-17T04:09:58.213","status":"Modified","description":"Akka HTTP 10.1.x before 10.1.15 and 10.2.x before 10.2.7 can encounter stack exhaustion while parsing HTTP headers, which allows a remote attacker to conduct a Denial of Service attack by sending a User-Agent header with deeply nested comments.","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-674"],"references":["http://packetstormsecurity.com/files/167018/Akka-HTTP-10.1.14-Denial-Of-Service.html","https://akka.io/blog/","https://akka.io/blog/news/2021/11/02/akka-http-10.2.7-released","https://akka.io/blog/news/2021/11/22/akka-http-10.1.15-released","https://doc.akka.io/docs/akka-http/current/security/2021-CVE-2021-42697-stack-overflow-parsing-user-agent.html"],"products":["akka:http_server"],"source":"nvd","synced_at":"2026-10-19T21:24:39.218183596+00:00"},"epss":{"cve":"CVE-2021-42697","score":0.36139,"percentile":0.98475,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-3hw2-h67c-wq66","url":"https://osv.dev/vulnerability/GHSA-3hw2-h67c-wq66","summary":"Uncontrolled Recursion in Akka HTTP","modified":"2025-09-30T18:16:55.386086Z","packages":[{"ecosystem":"Maven","name":"com.typesafe.akka:akka-http-core_2.13.0-RC3","purl":"pkg:maven/com.typesafe.akka/akka-http-core_2.13.0-RC3","ranges":[">=10.1.0"],"fixed":[]},{"ecosystem":"Maven","name":"com.typesafe.akka:akka-http-core_2.13.0-RC2","purl":"pkg:maven/com.typesafe.akka/akka-http-core_2.13.0-RC2","ranges":[">=10.1.0"],"fixed":[]},{"ecosystem":"Maven","name":"com.typesafe.akka:akka-http-core_2.13.0-M5","purl":"pkg:maven/com.typesafe.akka/akka-http-core_2.13.0-M5","ranges":[">=10.1.0"],"fixed":[]},{"ecosystem":"Maven","name":"com.typesafe.akka:aakka-http-core_2.13.0-M3","purl":"pkg:maven/com.typesafe.akka/aakka-http-core_2.13.0-M3","ranges":[">=10.1.0"],"fixed":[]},{"ecosystem":"Maven","name":"com.typesafe.akka:akka-http-core_2.13","purl":"pkg:maven/com.typesafe.akka/akka-http-core_2.13","ranges":[">=10.1.0 <10.1.15"],"fixed":["10.1.15"]},{"ecosystem":"Maven","name":"com.typesafe.akka:akka-http-core_2.13","purl":"pkg:maven/com.typesafe.akka/akka-http-core_2.13","ranges":[">=10.2.0-M1 <10.2.7"],"fixed":["10.2.7"]},{"ecosystem":"Maven","name":"com.typesafe.akka:akka-http-core_2.12","purl":"pkg:maven/com.typesafe.akka/akka-http-core_2.12","ranges":[">=10.1.0 <10.1.15"],"fixed":["10.1.15"]},{"ecosystem":"Maven","name":"com.typesafe.akka:akka-http-core_2.12","purl":"pkg:maven/com.typesafe.akka/akka-http-core_2.12","ranges":[">=10.2.0-M1 <10.2.7"],"fixed":["10.2.7"]},{"ecosystem":"Maven","name":"com.typesafe.akka:akka-http-core_2.11","purl":"pkg:maven/com.typesafe.akka/akka-http-core_2.11","ranges":[">=10.1.0 <10.1.15"],"fixed":["10.1.15"]}]}],"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."]}