{"id":"CVE-2021-20231","title":"A flaw was found in gnutls","summary":"A flaw was found in gnutls. A use after free issue in client sending key_share extension may lead to memory corruption and other consequences.","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"gnu","product":"gnutls","affected":["gnutls >= 3.6.3, < 3.7.1","enterprise_linux = 8.0","fedora = 34","active_iq_unified_manager","e-series_performance_analyzer"],"patched":["gnutls 3.7.1"],"published":"2021-03-12","updated":"2026-10-14","sourceUpdated":"2026-10-14T11:16:51.423","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-20231","references":[{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=1922276","label":"secalert@redhat.com"},{"url":"https://lists.apache.org/thread.html/r50661d6f0082709aad9a584431b59ec364f9974b63b07e0800230168%40%3Cissues.spark.apache.org%3E","label":"secalert@redhat.com"},{"url":"https://lists.apache.org/thread.html/r5d4001031e7790d8c6396c499522b4ed2aab782da87b1a14184793bb%40%3Cissues.spark.apache.org%3E","label":"secalert@redhat.com"},{"url":"https://lists.apache.org/thread.html/r5f88bed447742fcc5c47bf1c7be965ef450131914a6e1f85feba2779%40%3Cissues.spark.apache.org%3E","label":"secalert@redhat.com"},{"url":"https://lists.apache.org/thread.html/r6ac143ba6dd98bd4bf6bf010d46e56e254056459721ba18822d611f7%40%3Cissues.spark.apache.org%3E","label":"secalert@redhat.com"},{"url":"https://lists.apache.org/thread.html/r9cbc69e57276413788e90a6ee16c7c034ea4258d31935b70db2bd158%40%3Cissues.spark.apache.org%3E","label":"secalert@redhat.com"},{"url":"https://lists.apache.org/thread.html/rcd70a4c88a47a75fd2d5f3ffb7cee8c2a18c713320bd90fdcb57495f%40%3Cissues.spark.apache.org%3E","label":"secalert@redhat.com"},{"url":"https://lists.apache.org/thread.html/rf5e1256d870193def4a82ad89ab95e63943a313b5ff0d81aa87e4532%40%3Cissues.spark.apache.org%3E","label":"secalert@redhat.com"},{"url":"https://lists.apache.org/thread.html/rfd5273d72d244178441e6904a2f2b41a3268f569e8092ea0b3b2bb20%40%3Cissues.spark.apache.org%3E","label":"secalert@redhat.com"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OSLAE6PP33A7VYRYMYMUVB3U6B26GZER/","label":"secalert@redhat.com"},{"url":"https://security.netapp.com/advisory/ntap-20210416-0005/","label":"secalert@redhat.com"},{"url":"https://www.gnutls.org/security-new.html#GNUTLS-SA-2021-03-10","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=1922276","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r50661d6f0082709aad9a584431b59ec364f9974b63b07e0800230168%40%3Cissues.spark.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r5d4001031e7790d8c6396c499522b4ed2aab782da87b1a14184793bb%40%3Cissues.spark.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r5f88bed447742fcc5c47bf1c7be965ef450131914a6e1f85feba2779%40%3Cissues.spark.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r6ac143ba6dd98bd4bf6bf010d46e56e254056459721ba18822d611f7%40%3Cissues.spark.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r9cbc69e57276413788e90a6ee16c7c034ea4258d31935b70db2bd158%40%3Cissues.spark.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rcd70a4c88a47a75fd2d5f3ffb7cee8c2a18c713320bd90fdcb57495f%40%3Cissues.spark.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rf5e1256d870193def4a82ad89ab95e63943a313b5ff0d81aa87e4532%40%3Cissues.spark.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rfd5273d72d244178441e6904a2f2b41a3268f569e8092ea0b3b2bb20%40%3Cissues.spark.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OSLAE6PP33A7VYRYMYMUVB3U6B26GZER/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210416-0005/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.gnutls.org/security-new.html#GNUTLS-SA-2021-03-10","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-398330.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd"],"epss":0.03751,"epssPercentile":0.89646,"ingestedAt":"2026-10-14T11:27:22.120Z","slug":"CVE-2021-20231","body":"## Overview\n\nA flaw was found in gnutls. A use after free issue in client sending key_share extension may lead to memory corruption and other consequences.\n\n## Affected\n\n- `gnutls >= 3.6.3, < 3.7.1`\n- `enterprise_linux = 8.0`\n- `fedora = 34`\n- `active_iq_unified_manager`\n- `e-series_performance_analyzer`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `gnutls 3.7.1`","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":53.9,"likelihood":0.8,"exploitation":0,"ransomware":0},"changes":[]}