CVE-2021-3449

NULL pointer deref in signature_algorithms processing

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).

Category

5.9
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 13.86% Top 10%
Vendor Advisory cisco.com Vendor Advisory debian.org Vendor Advisory gentoo.org Vendor Advisory fedoraproject.org Vendor Advisory openssl.org
Affected: OpenSSL OpenSSL
Published at:
Updated at:

References

Link Tags
https://www.openssl.org/news/secadv/20210325.txt vendor advisory
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=fb9fa6b51defd48157eeb207f52181f735d96148
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJd third party advisory vendor advisory
https://www.debian.org/security/2021/dsa-4875 third party advisory vendor advisory
http://www.openwall.com/lists/oss-security/2021/03/27/1 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/03/27/2 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/03/28/3 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/03/28/4 third party advisory mailing list
https://security.gentoo.org/glsa/202103-03 third party advisory vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCBFLLVQVILIVGZMBJL3IXZGKWQISYNP/ vendor advisory
https://www.oracle.com/security-alerts/cpuApr2021.html third party advisory patch
https://www.tenable.com/security/tns-2021-10 third party advisory
https://www.tenable.com/security/tns-2021-09 third party advisory
https://security.netapp.com/advisory/ntap-20210513-0002/ third party advisory
https://security.netapp.com/advisory/ntap-20210326-0006/ third party advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.asc third party advisory
https://www.tenable.com/security/tns-2021-06 third party advisory
https://www.tenable.com/security/tns-2021-05 third party advisory
https://kc.mcafee.com/corporate/index?page=content&id=SB10356 third party advisory
https://www.oracle.com//security-alerts/cpujul2021.html third party advisory patch
https://cert-portal.siemens.com/productcert/pdf/ssa-772220.pdf third party advisory patch
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845 third party advisory
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013 third party advisory
https://lists.debian.org/debian-lts-announce/2021/08/msg00029.html third party advisory mailing list
https://www.oracle.com/security-alerts/cpuoct2021.html third party advisory
https://www.oracle.com/security-alerts/cpuapr2022.html third party advisory patch
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf third party advisory
https://www.oracle.com/security-alerts/cpujul2022.html third party advisory
https://security.netapp.com/advisory/ntap-20240621-0006/

Frequently Asked Questions

What is the severity of CVE-2021-3449?
CVE-2021-3449 has been scored as a medium severity vulnerability.
How to fix CVE-2021-3449?
To fix CVE-2021-3449, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-3449 being actively exploited in the wild?
It is possible that CVE-2021-3449 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~14% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-3449?
CVE-2021-3449 affects OpenSSL OpenSSL.
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