{"id":"CVE-2020-1967","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-1967","generatedAt":"2026-10-28T05:27:01.804Z","title":"Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the \"signature_algorithms_cert\" TLS extension.","description":"Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the \"signature_algorithms_cert\" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).","published":"2020-04-21T14:15:11.000Z","lastModified":"2026-10-08T21:17:25.000Z","status":"Modified","sourceIdentifier":"openssl-security@openssl.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-476"],"affected":["openssl/openssl","debian/debian linux","freebsd/freebsd","fedoraproject/fedora","oracle/application server","oracle/enterprise manager base platform","oracle/enterprise manager for storage management","oracle/enterprise manager ops center","oracle/http server","oracle/jd edwards world security","oracle/mysql","oracle/mysql connectors","oracle/mysql enterprise monitor","oracle/mysql workbench","oracle/peoplesoft enterprise peopletools","netapp/active iq unified manager","netapp/e-series performance analyzer","netapp/oncommand insight","netapp/oncommand workflow automation","netapp/smi-s provider","netapp/snapcenter","netapp/steelstore cloud integrated storage","broadcom/fabric operating system","opensuse/leap","jdedwards/enterpriseone","tenable/log correlation engine"],"epss":{"score":0.53336,"percentile":0.9898,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 53.3%, higher than 99% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.html","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.html","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"http://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.html","tags":["Third Party Advisory","VDB Entry"],"source":"openssl-security@openssl.org"},{"url":"http://seclists.org/fulldisclosure/2020/May/5","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"http://www.openwall.com/lists/oss-security/2020/04/22/2","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=eb563247aef3e83dda7679c43f9649270462e5b1","source":"openssl-security@openssl.org"},{"url":"https://github.com/irsl/CVE-2020-1967","tags":["Exploit","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440","tags":["Third Party 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Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.gentoo.org/glsa/202004-10","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.netapp.com/advisory/ntap-20200424-0003/","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.netapp.com/advisory/ntap-20200717-0004/","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.debian.org/security/2020/dsa-4661","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.openssl.org/news/secadv/20200421.txt","tags":["Vendor Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","tags":["Patch","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.oracle.com/security-alerts/cpuApr2021.html","tags":["Patch","Third Party 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Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.tenable.com/security/tns-2020-04","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.tenable.com/security/tns-2020-11","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.tenable.com/security/tns-2021-10","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.html","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://seclists.org/fulldisclosure/2020/May/5","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2020/04/22/2","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=eb563247aef3e83dda7679c43f9649270462e5b1","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/irsl/CVE-2020-1967","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r66ea9c436da150683432db5fbc8beb8ae01886c6459ac30c2cea7345%40%3Cdev.tomcat.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r94d6ac3f010a38fccf4f432b12180a13fa1cf303559bd805648c9064%40%3Cdev.tomcat.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r9a41e304992ce6aec6585a87842b4f2e692604f5c892c37e3b0587ee%40%3Cdev.tomcat.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DDHOAATPWJCXRNFMJ2SASDBBNU5RJONY/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EXDDAOWSAIEFQNBHWYE6PPYFV4QXGMCD/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XVEP3LAK4JSPRXFO4QF4GG2IVXADV3SO/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.FreeBSD.org/advisories/FreeBSD-SA-20:11.openssl.asc","tags":["Patch","Third 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Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuApr2021.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2021.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujul2020.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuoct2020.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.synology.com/security/advisory/Synology_SA_20_05","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.synology.com/security/advisory/Synology_SA_20_05_OpenSSL","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-1967","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}