{"id":"CVE-2021-30639","details":"A vulnerability in Apache Tomcat allows an attacker to remotely trigger a denial of service. An error introduced as part of a change to improve error handling during non-blocking I/O meant that the error flag associated with the Request object was not reset between requests. This meant that once a non-blocking I/O error occurred, all future requests handled by that request object would fail. Users were able to trigger non-blocking I/O errors, e.g. by dropping a connection, thereby creating the possibility of triggering a DoS. Applications that do not use non-blocking I/O are not exposed to this vulnerability. This issue affects Apache Tomcat 10.0.3 to 10.0.4; 9.0.44; 8.5.64.","aliases":["BIT-tomcat-2021-30639","GHSA-44qp-qhfv-c7f6"],"modified":"2026-04-10T04:32:15.233110Z","published":"2021-07-12T15:15:08.333Z","references":[{"type":"WEB","url":"https://lists.apache.org/thread.html/r79a7c019712b39aedf7cf4da9276d80610f04441b2a4f6506cb2daaf%40%3Cdev.tomcat.apache.org%3E"},{"type":"WEB","url":"https://lists.apache.org/thread.html/r79a7c019712b39aedf7cf4da9276d80610f04441b2a4f6506cb2daaf%40%3Cusers.tomcat.apache.org%3E"},{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202208-34"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20210827-0007/"},{"type":"ADVISORY","url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10366"},{"type":"ADVISORY","url":"https://lists.apache.org/thread.html/rd84fae1f474597bdf358f5bdc0a5c453c507bd527b83e8be6b5ea3f4%40%3Cannounce.tomcat.apache.org%3E"},{"type":"FIX","url":"https://www.oracle.com/security-alerts/cpujan2022.html"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/apache/tomcat","events":[{"introduced":"0"},{"last_affected":"c47f86adea090175669df8b2ca04c93050bcaf8c"},{"introduced":"0"},{"last_affected":"7b4007a6a77300056f4681b064d7332c2284cbdd"},{"introduced":"0"},{"last_affected":"50c2c705bb74e35ada28147aa2649cb43398b3f9"},{"introduced":"0"},{"last_affected":"ec47d24b49bc176f47b786bc96248e94d1823685"}],"database_specific":{"versions":[{"introduced":"0"},{"last_affected":"8.5.64"},{"introduced":"0"},{"last_affected":"9.0.44"},{"introduced":"0"},{"last_affected":"10.0.3"},{"introduced":"0"},{"last_affected":"10.0.4"}]}}],"versions":["10.0.3","10.0.4","8.5.64","9.0.44"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-30639.json","unresolved_ranges":[{"events":[{"introduced":"0"},{"fixed":"5.10.0"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-NA"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_1"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_10"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_2"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_3"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_4"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_5"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_6"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_7"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_8"}]},{"events":[{"introduced":"0"},{"last_affected":"5.10.0-update_9"}]},{"events":[{"introduced":"0"},{"fixed":"23.1"}]}]}}],"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"}]}