CVE-2021-3449
MEDIUMEPSS 99th pctlDescription
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).
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Very high risk: more likely to be exploited than 99% of all known CVEs.
References
- http://www.openwall.com/lists/oss-security/2021/03/27/1
- http://www.openwall.com/lists/oss-security/2021/03/27/2
- http://www.openwall.com/lists/oss-security/2021/03/28/3
- http://www.openwall.com/lists/oss-security/2021/03/28/4
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=fb9fa6b51defd48157eeb207f52181f735d96148
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845
- https://kc.mcafee.com/corporate/index?page=content&id=SB10356
- https://lists.debian.org/debian-lts-announce/2021/08/msg00029.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013
- https://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.asc
- https://security.gentoo.org/glsa/202103-03
- https://security.netapp.com/advisory/ntap-20210326-0006/
- https://security.netapp.com/advisory/ntap-20210513-0002/
- https://security.netapp.com/advisory/ntap-20240621-0006/
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJd
- https://www.debian.org/security/2021/dsa-4875
- https://www.openssl.org/news/secadv/20210325.txt
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.tenable.com/security/tns-2021-05
- https://www.tenable.com/security/tns-2021-06
- https://www.tenable.com/security/tns-2021-09
- https://www.tenable.com/security/tns-2021-10
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.