Segmentation fault in SSL_check_chain

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).

Scores

EPSS (exploitation in 30 days)

53.3% · top 1.0% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

• NULL pointer dereference
• CWE-476 (opens in a new tab)All about CWE-476 and its CVEs

Affected products

• OpenSSL · OpenSSL

  • affected Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f)

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• crates.ioopenssl-srcGHSA-jq65-29v4-4x35 (opens in a new tab)

References (32)

• FreeBSD-SA-20:11 (opens in a new tab)vendor-advisoryx_refsource_FREEBSDx_transferred
• DSA-4661 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
• [oss-security] 20200422 [CVE-2020-1967] OpenSSL 1.1.1d+ Segmentation fault in SSL_check_chain (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [tomcat-dev] 20200422 Time for Tomcat Native 1.2.24? (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [tomcat-dev] 20200422 Re: Time for Tomcat Native 1.2.24? (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [tomcat-dev] 20200423 Re: Time for Tomcat Native 1.2.24? (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• GLSA-202004-10 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
• FEDORA-2020-fcc91a28e8 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
• FEDORA-2020-da2d1ef2d7 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
• 20200501 CVE-2020-1967: proving sigalg != NULL (opens in a new tab)mailing-listx_refsource_FULLDISCx_transferred
• FEDORA-2020-d7b29838f6 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
• openSUSE-SU-2020:0933 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• openSUSE-SU-2020:0945 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
• https://www.oracle.com/security-alerts/cpujul2020.html (opens in a new tab)x_refsource_MISCx_transferred
• https://www.tenable.com/security/tns-2020-03 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://www.openssl.org/news/secadv/20200421.txt (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=eb563247aef3e83dda7679c43f9649270462e5b1 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://security.netapp.com/advisory/ntap-20200424-0003/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://www.synology.com/security/advisory/Synology_SA_20_05_OpenSSL (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://github.com/irsl/CVE-2020-1967 (opens in a new tab)x_refsource_MISCx_transferred
• http://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.html (opens in a new tab)x_refsource_MISCx_transferred
• https://www.synology.com/security/advisory/Synology_SA_20_05 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://www.tenable.com/security/tns-2020-04 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://www.oracle.com/security-alerts/cpuoct2020.html (opens in a new tab)x_refsource_MISCx_transferred
• https://security.netapp.com/advisory/ntap-20200717-0004/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://www.oracle.com/security-alerts/cpujan2021.html (opens in a new tab)x_refsource_MISCx_transferred
• https://www.tenable.com/security/tns-2020-11 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://www.oracle.com/security-alerts/cpuApr2021.html (opens in a new tab)x_refsource_MISCx_transferred
• https://www.tenable.com/security/tns-2021-10 (opens in a new tab)x_refsource_CONFIRMx_transferred
• https://www.oracle.com//security-alerts/cpujul2021.html (opens in a new tab)x_refsource_MISCx_transferred
• https://www.oracle.com/security-alerts/cpuoct2021.html (opens in a new tab)x_refsource_MISCx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-jq65-29v4-4x35 (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2020-1967](https://trackcve.app/badge/CVE-2020-1967.svg)](https://trackcve.app/cve/CVE-2020-1967)

Record last updated 8 Oct 2026, 21:03 UTC.