HOME VULNERABILITIESCVE-2020-1967

HIGH

CVE-2020-1967

CWE-476Published: April 21, 2020· Updated: Jun 17, 2026

7.5

CVSS v3.1

Official 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).

Technical Analysis

CVE-2020-1967 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges Req.None

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

broadcom1 product(s)

fabric operating system

Debian1 product(s)

debian linux

Fedora1 product(s)

fedora

freebsd1 product(s)

freebsd

jdedwards1 product(s)

enterpriseone

netapp7 product(s)

active iq unified managere-series performance analyzeroncommand insightoncommand workflow automationsmi-s providersnapcentersteelstore cloud integrated storage

OpenSSL1 product(s)

openssl

openSUSE1 product(s)

leap

Oracle11 product(s)

application serverenterprise manager base platformenterprise manager for storage managemententerprise manager ops centerhttp serverjd edwards world securitymysqlmysql connectorsmysql enterprise monitormysql workbenchpeoplesoft enterprise peopletools

tenable1 product(s)

log correlation engine

Source: NVD CPE · 34 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://security.FreeBSD.org/advisories/FreeBSD-SA-20:11.openssl.asc

PATCHhttps://www.oracle.com//security-alerts/cpujul2021.html

PATCHhttps://www.oracle.com/security-alerts/cpuApr2021.html

PATCHhttps://www.oracle.com/security-alerts/cpujan2021.html

PATCHhttps://www.oracle.com/security-alerts/cpuoct2020.html

PATCHhttps://www.oracle.com/security-alerts/cpuoct2021.html

PATCHhttps://security.FreeBSD.org/advisories/FreeBSD-SA-20:11.openssl.asc

PATCHhttps://www.oracle.com//security-alerts/cpujul2021.html

PATCHhttps://www.oracle.com/security-alerts/cpuApr2021.html

PATCHhttps://www.oracle.com/security-alerts/cpujan2021.html

PATCHhttps://www.oracle.com/security-alerts/cpuoct2020.html

PATCHhttps://www.oracle.com/security-alerts/cpuoct2021.html

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.html

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.html

ADVISORYhttp://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.html

ADVISORYhttp://seclists.org/fulldisclosure/2020/May/5

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/04/22/2

ADVISORYhttps://github.com/irsl/CVE-2020-1967

ADVISORYhttps://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440

ADVISORYhttps://security.gentoo.org/glsa/202004-10

ADVISORYhttps://security.netapp.com/advisory/ntap-20200424-0003/

ADVISORYhttps://security.netapp.com/advisory/ntap-20200717-0004/

ADVISORYhttps://www.debian.org/security/2020/dsa-4661

ADVISORYhttps://www.openssl.org/news/secadv/20200421.txt

ADVISORYhttps://www.oracle.com/security-alerts/cpujul2020.html

ADVISORYhttps://www.synology.com/security/advisory/Synology_SA_20_05

ADVISORYhttps://www.synology.com/security/advisory/Synology_SA_20_05_OpenSSL

ADVISORYhttps://www.tenable.com/security/tns-2020-03

ADVISORYhttps://www.tenable.com/security/tns-2020-04

ADVISORYhttps://www.tenable.com/security/tns-2020-11

ADVISORYhttps://www.tenable.com/security/tns-2021-10

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.html

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.html

ADVISORYhttp://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.html

ADVISORYhttp://seclists.org/fulldisclosure/2020/May/5

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/04/22/2

ADVISORYhttps://github.com/irsl/CVE-2020-1967

ADVISORYhttps://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440

ADVISORYhttps://security.gentoo.org/glsa/202004-10

ADVISORYhttps://security.netapp.com/advisory/ntap-20200424-0003/

ADVISORYhttps://security.netapp.com/advisory/ntap-20200717-0004/

ADVISORYhttps://www.debian.org/security/2020/dsa-4661

ADVISORYhttps://www.openssl.org/news/secadv/20200421.txt

ADVISORYhttps://www.oracle.com/security-alerts/cpujul2020.html

ADVISORYhttps://www.synology.com/security/advisory/Synology_SA_20_05

ADVISORYhttps://www.synology.com/security/advisory/Synology_SA_20_05_OpenSSL

ADVISORYhttps://www.tenable.com/security/tns-2020-03

ADVISORYhttps://www.tenable.com/security/tns-2020-04

ADVISORYhttps://www.tenable.com/security/tns-2020-11

ADVISORYhttps://www.tenable.com/security/tns-2021-10

All References (64)

→

http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.htmlMailing List · Third Party Advisory

→

http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.htmlMailing List · Third Party Advisory

→

http://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.htmlThird Party Advisory · VDB Entry

→

http://seclists.org/fulldisclosure/2020/May/5Mailing List · Third Party Advisory

→

http://www.openwall.com/lists/oss-security/2020/04/22/2Mailing List · Third Party Advisory

→

https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=eb563247aef3e83dda7679c43f9649270462e5b1

→

https://github.com/irsl/CVE-2020-1967Exploit · Third Party Advisory

→

https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440Third Party Advisory

→

https://lists.apache.org/thread.html/r66ea9c436da150683432db5fbc8beb8ae01886c6459ac30c2cea7345%40%3Cdev.tomcat.apache.org%3E

→

https://lists.apache.org/thread.html/r94d6ac3f010a38fccf4f432b12180a13fa1cf303559bd805648c9064%40%3Cdev.tomcat.apache.org%3E

→

https://lists.apache.org/thread.html/r9a41e304992ce6aec6585a87842b4f2e692604f5c892c37e3b0587ee%40%3Cdev.tomcat.apache.org%3E

→

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DDHOAATPWJCXRNFMJ2SASDBBNU5RJONY/

→

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EXDDAOWSAIEFQNBHWYE6PPYFV4QXGMCD/

→

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XVEP3LAK4JSPRXFO4QF4GG2IVXADV3SO/

→

https://security.FreeBSD.org/advisories/FreeBSD-SA-20:11.openssl.ascPatch · Third Party Advisory

Quick Facts

CVE IDCVE-2020-1967

CVSS Score7.5 / 10

SeverityHIGH

WeaknessCWE-476

CISA KEVNo

Affected10 vendor(s)

PublishedApr 21, 2020

Related CVEs (CWE-476)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2020-1967 in threat intel feeds
→Review IDS/IPS signatures for exploitation attempts

Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.

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