{"id":"CVE-2021-3449","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-3449","generatedAt":"2026-11-05T01:35:23.483Z","title":"An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client.","description":"An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack. A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS clients are not impacted by this issue. All OpenSSL 1.1.1 versions are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1-1.1.1j).","published":"2021-03-25T15:15:13.000Z","lastModified":"2026-10-08T22:17:11.000Z","status":"Modified","sourceIdentifier":"openssl-security@openssl.org","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-476"],"affected":["openssl/openssl","debian/debian linux","freebsd/freebsd","netapp/active iq unified manager","netapp/cloud volumes ontap mediator","netapp/e-series performance analyzer","netapp/oncommand insight","netapp/oncommand workflow automation","netapp/ontap select deploy administration utility","netapp/santricity smi-s provider","netapp/snapcenter","netapp/storagegrid","tenable/log correlation engine","tenable/nessus","tenable/nessus network monitor","tenable/tenable.sc","fedoraproject/fedora","mcafee/web gateway","mcafee/web gateway cloud service","checkpoint/quantum security management firmware","checkpoint/multi-domain management firmware","checkpoint/quantum security gateway firmware","oracle/communications communications policy management","oracle/enterprise manager for storage management","oracle/essbase","oracle/graalvm","oracle/jd edwards enterpriseone tools","oracle/jd edwards world security","oracle/mysql connectors","oracle/mysql server","oracle/mysql workbench","oracle/peoplesoft enterprise peopletools","oracle/primavera unifier","oracle/secure backup","oracle/secure global desktop","oracle/zfs storage appliance kit","sonicwall/sma100 firmware","sonicwall/capture client","sonicwall/sonicos","siemens/ruggedcom rcm1224 firmware","siemens/scalance lpe9403 firmware","siemens/scalance m-800 firmware","siemens/scalance s602 firmware","siemens/scalance s612 firmware","siemens/scalance s615 firmware","siemens/scalance s623 firmware","siemens/scalance s627-2m firmware","siemens/scalance sc-600 firmware","siemens/scalance w700 firmware","siemens/scalance w1700 firmware","siemens/scalance xb-200 firmware","siemens/scalance xc-200 firmware","siemens/scalance xf-200ba firmware","siemens/scalance xm-400 firmware","siemens/scalance xp-200 firmware","siemens/scalance xr-300wg firmware","siemens/scalance xr524-8c firmware","siemens/scalance xr526-8c firmware","siemens/scalance xr528-6m firmware","siemens/scalance xr552-12 firmware"],"epss":{"score":0.63542,"percentile":0.99214,"date":"2026-11-03","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 63.5%, higher than 99% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://www.openwall.com/lists/oss-security/2021/03/27/1","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"http://www.openwall.com/lists/oss-security/2021/03/27/2","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"http://www.openwall.com/lists/oss-security/2021/03/28/3","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"http://www.openwall.com/lists/oss-security/2021/03/28/4","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf","tags":["Patch","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=fb9fa6b51defd48157eeb207f52181f735d96148","source":"openssl-security@openssl.org"},{"url":"https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10356","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/08/msg00029.html","tags":["Mailing List","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/","source":"openssl-security@openssl.org"},{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.asc","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.gentoo.org/glsa/202103-03","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.netapp.com/advisory/ntap-20210326-0006/","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.netapp.com/advisory/ntap-20210513-0002/","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.netapp.com/advisory/ntap-20240621-0006/","source":"openssl-security@openssl.org"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJd","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.debian.org/security/2021/dsa-4875","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.openssl.org/news/secadv/20210325.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 Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Patch","Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.oracle.com/security-alerts/cpujul2022.html","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.tenable.com/security/tns-2021-05","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.tenable.com/security/tns-2021-06","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.tenable.com/security/tns-2021-09","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://www.openwall.com/lists/oss-security/2021/03/27/1","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2021/03/27/2","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2021/03/28/3","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2021/03/28/4","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=fb9fa6b51defd48157eeb207f52181f735d96148","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10356","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/08/msg00029.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.asc","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202103-03","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210326-0006/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210513-0002/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20240621-0006/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJd","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2021/dsa-4875","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.openssl.org/news/secadv/20210325.txt","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","tags":["Patch","Third Party 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/cpuapr2022.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujul2022.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.tenable.com/security/tns-2021-05","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.tenable.com/security/tns-2021-06","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.tenable.com/security/tns-2021-09","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.tenable.com/security/tns-2021-10","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-3449","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."}