{"id":"UBUNTU-CVE-2021-3842","details":"nltk is vulnerable to Inefficient Regular Expression Complexity","modified":"2026-02-05T14:26:28.687851Z","published":"2022-01-04T15:15:00Z","related":["USN-7365-1"],"upstream":["CVE-2021-3842"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-3842"},{"type":"REPORT","url":"https://huntr.dev/bounties/761a761e-2be2-430a-8d92-6f74ffe9866a/"},{"type":"REPORT","url":"https://github.com/nltk/nltk/pull/2906"},{"type":"REPORT","url":"https://github.com/nltk/nltk/commit/2a50a3edc9d35f57ae42a921c621edc160877f4d"},{"type":"REPORT","url":"https://github.com/nltk/nltk/commit/2a50a3edc9d35f57ae42a921c621edc160877f4d"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-3842"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-7365-1"}],"affected":[{"package":{"name":"nltk","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/nltk@2.0~b9-0ubuntu4.1~esm4?arch=source&distro=esm-infra-legacy/trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0~b9-0ubuntu4.1~esm4"}]}],"versions":["2.0~b9-0ubuntu4","2.0~b9-0ubuntu4.1~esm2"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro","binaries":[{"binary_name":"python-nltk","binary_version":"2.0~b9-0ubuntu4.1~esm4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3842.json"}},{"package":{"name":"nltk","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/nltk@3.1-1ubuntu0.1+esm2?arch=source&distro=esm-apps/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1-1ubuntu0.1+esm2"}]}],"versions":["3.0.4-1","3.0.5-1","3.1-1","3.1-1ubuntu0.1","3.1-1ubuntu0.1+esm1"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"python-nltk","binary_version":"3.1-1ubuntu0.1+esm2"},{"binary_name":"python3-nltk","binary_version":"3.1-1ubuntu0.1+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3842.json"}},{"package":{"name":"nltk","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/nltk@3.2.5-1ubuntu0.1+esm2?arch=source&distro=esm-apps/bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.2.5-1ubuntu0.1+esm2"}]}],"versions":["3.2.4-1","3.2.5-1","3.2.5-1ubuntu0.1","3.2.5-1ubuntu0.1+esm1"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"python-nltk","binary_version":"3.2.5-1ubuntu0.1+esm2"},{"binary_name":"python3-nltk","binary_version":"3.2.5-1ubuntu0.1+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3842.json"}},{"package":{"name":"nltk","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/nltk@3.4.5-2ubuntu0.1~esm2?arch=source&distro=esm-apps/focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.5-2ubuntu0.1~esm2"}]}],"versions":["3.4.5-1","3.4.5-2","3.4.5-2ubuntu0.1~esm1"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"python3-nltk","binary_version":"3.4.5-2ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3842.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"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"}]}