{"id":"UBUNTU-CVE-2021-43980","details":"The simplified implementation of blocking reads and writes introduced in Tomcat 10 and back-ported to Tomcat 9.0.47 onwards exposed a long standing (but extremely hard to trigger) concurrency bug in Apache Tomcat 10.1.0 to 10.1.0-M12, 10.0.0-M1 to 10.0.18, 9.0.0-M1 to 9.0.60 and 8.5.0 to 8.5.77 that could cause client connections to share an Http11Processor instance resulting in responses, or part responses, to be received by the wrong client.","modified":"2026-07-15T19:45:19.996963590Z","published":"2022-09-28T14:15:00Z","upstream":["CVE-2021-43980"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-43980"},{"type":"REPORT","url":"https://lists.apache.org/thread/3jjqbsp6j88b198x5rmg99b1qr8ht3g3"},{"type":"REPORT","url":"https://github.com/apache/tomcat/commit/170e0f792bd18ff031677890ba2fe50eb7a376c1"},{"type":"REPORT","url":"https://github.com/apache/tomcat/commit/4a00b0c0890538b9d3107eef8f2e0afadd119beb"},{"type":"REPORT","url":"http://www.openwall.com/lists/oss-security/2022/09/28/1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-43980"}],"affected":[{"package":{"name":"tomcat8","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/tomcat8?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.5.21-1ubuntu1","8.5.29-1","8.5.30-1","8.5.30-1ubuntu1","8.5.30-1ubuntu1.2","8.5.30-1ubuntu1.3","8.5.30-1ubuntu1.4","8.5.39-1ubuntu1~18.04.1","8.5.39-1ubuntu1~18.04.2","8.5.39-1ubuntu1~18.04.3","8.5.39-1ubuntu1~18.04.3+esm1","8.5.39-1ubuntu1~18.04.3+esm2","8.5.39-1ubuntu1~18.04.3+esm3","8.5.39-1ubuntu1~18.04.3+esm4","8.5.39-1ubuntu1~18.04.3+esm5","8.5.39-1ubuntu1~18.04.3+esm6"],"ecosystem_specific":{"binaries":[{"binary_name":"libtomcat8-embed-java","binary_version":"8.5.39-1ubuntu1~18.04.3+esm6"},{"binary_name":"libtomcat8-java","binary_version":"8.5.39-1ubuntu1~18.04.3+esm6"},{"binary_name":"tomcat8","binary_version":"8.5.39-1ubuntu1~18.04.3+esm6"},{"binary_name":"tomcat8-admin","binary_version":"8.5.39-1ubuntu1~18.04.3+esm6"},{"binary_version":"8.5.39-1ubuntu1~18.04.3+esm6","binary_name":"tomcat8-common"},{"binary_version":"8.5.39-1ubuntu1~18.04.3+esm6","binary_name":"tomcat8-docs"},{"binary_version":"8.5.39-1ubuntu1~18.04.3+esm6","binary_name":"tomcat8-examples"},{"binary_version":"8.5.39-1ubuntu1~18.04.3+esm6","binary_name":"tomcat8-user"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-43980.json"}},{"package":{"name":"tomcat9","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/tomcat9?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.0.16-3~18.04.1","9.0.16-3ubuntu0.18.04.1","9.0.16-3ubuntu0.18.04.2","9.0.16-3ubuntu0.18.04.2+esm1","9.0.16-3ubuntu0.18.04.2+esm2","9.0.16-3ubuntu0.18.04.2+esm3","9.0.16-3ubuntu0.18.04.2+esm4","9.0.16-3ubuntu0.18.04.2+esm5","9.0.16-3ubuntu0.18.04.2+esm6","9.0.16-3ubuntu0.18.04.2+esm7","9.0.16-3ubuntu0.18.04.2+esm8"],"ecosystem_specific":{"binaries":[{"binary_name":"libtomcat9-embed-java","binary_version":"9.0.16-3ubuntu0.18.04.2+esm8"},{"binary_version":"9.0.16-3ubuntu0.18.04.2+esm8","binary_name":"libtomcat9-java"},{"binary_version":"9.0.16-3ubuntu0.18.04.2+esm8","binary_name":"tomcat9"},{"binary_name":"tomcat9-admin","binary_version":"9.0.16-3ubuntu0.18.04.2+esm8"},{"binary_name":"tomcat9-common","binary_version":"9.0.16-3ubuntu0.18.04.2+esm8"},{"binary_name":"tomcat9-docs","binary_version":"9.0.16-3ubuntu0.18.04.2+esm8"},{"binary_name":"tomcat9-examples","binary_version":"9.0.16-3ubuntu0.18.04.2+esm8"},{"binary_version":"9.0.16-3ubuntu0.18.04.2+esm8","binary_name":"tomcat9-user"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-43980.json"}},{"package":{"name":"tomcat9","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/tomcat9?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.0.24-1","9.0.27-1","9.0.31-1","9.0.31-1ubuntu0.1","9.0.31-1ubuntu0.2","9.0.31-1ubuntu0.3","9.0.31-1ubuntu0.4","9.0.31-1ubuntu0.5","9.0.31-1ubuntu0.6","9.0.31-1ubuntu0.7","9.0.31-1ubuntu0.8","9.0.31-1ubuntu0.9","9.0.31-1ubuntu0.9+esm1","9.0.31-1ubuntu0.9+esm2","9.0.31-1ubuntu0.9+esm3"],"ecosystem_specific":{"binaries":[{"binary_name":"libtomcat9-embed-java","binary_version":"9.0.31-1ubuntu0.9+esm3"},{"binary_name":"libtomcat9-java","binary_version":"9.0.31-1ubuntu0.9+esm3"},{"binary_version":"9.0.31-1ubuntu0.9+esm3","binary_name":"tomcat9"},{"binary_name":"tomcat9-admin","binary_version":"9.0.31-1ubuntu0.9+esm3"},{"binary_version":"9.0.31-1ubuntu0.9+esm3","binary_name":"tomcat9-common"},{"binary_name":"tomcat9-docs","binary_version":"9.0.31-1ubuntu0.9+esm3"},{"binary_name":"tomcat9-examples","binary_version":"9.0.31-1ubuntu0.9+esm3"},{"binary_version":"9.0.31-1ubuntu0.9+esm3","binary_name":"tomcat9-user"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-43980.json"}},{"package":{"name":"tomcat9","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/tomcat9?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.0.43-3","9.0.54-1","9.0.55-1","9.0.58-1","9.0.58-1ubuntu0.1","9.0.58-1ubuntu0.1+esm1","9.0.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