CVE-2020-1967 — Segmentation fault in SSL_check_chain
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).
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 53.3% (30-day exploitation probability)+15
- Technical severity (high)+6
- Automatable exploitation (SSVC)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — security.FreeBSD.org (NIST National Vulnerability Database)
- Documented patch — www.oracle.com (NIST National Vulnerability Database)
- Documented patch — www.oracle.com (NIST National Vulnerability Database)
- Documented patch — www.oracle.com (NIST National Vulnerability Database)
- Documented patch — www.oracle.com (NIST National Vulnerability Database)
- Documented patch — www.oracle.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Broadcom Fabric Operating System, Debian Debian Linux, Fedoraproject Fedora…).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- EPSS ahead of 99% of scored CVEs: prioritize it in the patch queue.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Broadcom | Fabric Operating System | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Debian | Debian Linux | version 9.0version 10.0 | Vulnerable | NIST National Vulnerability Database |
| Fedoraproject | Fedora | version 31version 32version 30 | Vulnerable | NIST National Vulnerability Database |
| Freebsd | Freebsd | version 12.1 | Vulnerable | NIST National Vulnerability Database |
| Jdedwards | Enterpriseone | < 9.2.5.0 | Vulnerable | NIST National Vulnerability Database |
| Netapp | Active Iq Unified Manager | ≥ 9.5≥ 7.3 | Vulnerable | NIST National Vulnerability Database |
| Netapp | E-series Performance Analyzer | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Oncommand Insight | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Oncommand Workflow Automation | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Smi-s Provider | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Snapcenter | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Steelstore Cloud Integrated Storage | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Openssl | Openssl | ≥ 1.1.1d and ≤ 1.1.1f | Vulnerable | NIST National Vulnerability Database |
| Openssl | Openssl | version Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f) | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Opensuse | Leap | version 15.2version 15.1 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Application Server | version 12.1.3 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Enterprise Manager Base Platform | version 13.4.0.0 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Enterprise Manager For Storage Management | version 13.4.0.0version 13.3.0.0 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Enterprise Manager Ops Center | version 12.4.0 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Http Server | version 12.2.1.4.0 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Jd Edwards World Security | version a9.4 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Mysql | ≤ 5.6.48≥ 5.7.0 and ≤ 5.7.30≥ 8.0.0 and ≤ 8.0.20 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Mysql Connectors | ≤ 8.0.20 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Mysql Enterprise Monitor | ≥ 8.0.0 and ≤ 8.0.20≤ 4.0.12 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Mysql Workbench | ≤ 8.0.21 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Peoplesoft Enterprise Peopletools | version 8.58version 8.57version 8.56version 8.59 | Vulnerable | NIST National Vulnerability Database |
| Tenable | Log Correlation Engine | < 6.0.9 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.5 | CVSS 3.1 | High | 3.9 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
| 5.0 | CVSS 2.0 | Medium | 10.0 | 2.9 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 53.34%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · openssl/openssl
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 7.5
- Source status changed · → Modified
- Record created in this database
- 2020
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
32 on the record
- www.openssl.org/news/secadv/20200421.txt
- www.oracle.com/security-alerts/cpuoct2021.html
- www.oracle.com//security-alerts/cpujul2021.html
- www.oracle.com/security-alerts/cpujan2021.html
- www.oracle.com/security-alerts/cpuApr2021.html
- www.oracle.com/security-alerts/cpuoct2020.html
- security.FreeBSD.org/advisories/FreeBSD-SA-20:11.openssl.asc
- lists.apache.org/thread.html/r94d6ac3f010a38fccf4f432b12180a13fa1cf303559bd805648c9064
- seclists.org/fulldisclosure/2020/May/5
- www.synology.com/security/advisory/Synology_SA_20_05
- git.openssl.org/gitweb/
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.html
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.html
- www.debian.org/security/2020/dsa-4661
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DDHO
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EXDD
- www.tenable.com/security/tns-2020-04
- lists.apache.org/thread.html/r9a41e304992ce6aec6585a87842b4f2e692604f5c892c37e3b0587ee
- www.oracle.com/security-alerts/cpujul2020.html
- security.netapp.com/advisory/ntap-20200424-0003/
- lists.apache.org/thread.html/r66ea9c436da150683432db5fbc8beb8ae01886c6459ac30c2cea7345
- security.netapp.com/advisory/ntap-20200717-0004/
- kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440
- github.com/irsl/CVE-2020-1967
- www.openwall.com/lists/oss-security/2020/04/22/2
- www.tenable.com/security/tns-2020-11
- packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XVEP
- www.tenable.com/security/tns-2021-10
- www.synology.com/security/advisory/Synology_SA_20_05_OpenSSL
- www.tenable.com/security/tns-2020-03
- security.gentoo.org/glsa/202004-10
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-94587 A buffer overflow vulnerability exists in the WebTools administrative interface handling... 7d
- High CVE-2026-94577 A privilege escalation vulnerability exists in the internal Command-Line Interface (CLI)... 7d
- High CVE-2026-94579 An OS command injection vulnerability exists in the PAM (Pluggable Authentication Module) session... 7d
- Medium CVE-2026-94581 An OS command injection vulnerability exists in the REST API management interface of Brocade... 7d
- Medium CVE-2026-94586 A command injection vulnerability exists in the WebTools administrative interface handling... 7d
- High CVE-2026-94585 An authentication bypass vulnerability exists in the web management interface of Brocade Fabric... 7d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2020-1967 is "Segmentation fault in SSL_check_chain", rated High. It affects Fabric Operating System (Broadcom); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 53.34% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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