Description
The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a "purpose" has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named "purpose" values implemented in libcrypto perform this check. Therefore, where a purpose is set the certificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verification routines, but it can be overridden or removed by an application. In order to be affected, an application must explicitly set the X509_V_FLAG_X509_STRICT verification flag and either not set a purpose for the certificate verification or, in the case of TLS client or server applications, override the default purpose. OpenSSL versions 1.1.1h and newer 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 1.1.1h-1.1.1j).
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| OpenSSL | OpenSSL | Fixed in OpenSSL 1.1.1k (Affected 1.1.1h-1.1.1j) | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | openssl | 1.1.1k-1 | — |
| Debian 13 | openssl | 1.1.1k-1 | — |
| Debian 12 | openssl | 1.1.1k-1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | openssl +3 | 1:1.1.1g-15.el8_3 | RHSA-2021:1024 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Rhev Hypervisor 4 | redhat-virtualization-host +1 | 4.4.5-20210330.0.el8_3 | RHSA-2021:1189 |
| Red Hat JBoss Web Server 5 | jws5-tomcat-native | 1.2.25-4.redhat_4.el7jws | RHSA-2021:1195 |
| Red Hat JBoss Web Server 3 | tomcat-native | 1.2.23-24.redhat_24.ep7.el7 | RHSA-2021:1202 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +6 | 2.4.37-70.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_cluster-native | 1.3.14-20.Final_redhat_2.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_http2 | 1.15.7-14.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_jk +2 | 1.2.48-13.redhat_1.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_md | 1:2.0.8-33.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_security | 2.9.2-60.GA.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.37-70.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-nghttp2 +1 | 1.39.2-37.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl +4 | 1:1.1.1g-6.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl-chil | 1.0.0-5.jbcs.el7 | RHSA-2021:1199 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl-pkcs11 | 0.4.10-20.jbcs.el7 | RHSA-2021:1199 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | openssl | 1:1.1.1g-15.el8_3 | RLSA-2021:1024 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | nodejs12 | 12.22.2-4.16.1 | SUSE-SU-2021:2327-1 |
| SLES 15 SP2 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SLES 15 SP2 | nodejs12 | 12.22.2-4.16.1 | SUSE-SU-2021:2327-1 |
| SLES 15 SP1 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SLES 15 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SLES 12 | nodejs10 | 10.24.1-1.39.1 | SUSE-SU-2021:2323-1 |
| SLES 12 | nodejs12 | 12.22.2-1.32.1 | SUSE-SU-2021:2326-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP1 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SLES for SAP 15 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SLE HPC 15 SP1 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SLE HPC 15 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SUSE Manager Server 4.0 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SUSE Manager Retail Branch Server 4.0 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SUSE Manager Proxy 4.0 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
| SUSE Enterprise Storage 6 | nodejs10 | 10.24.1-1.36.1 | SUSE-SU-2021:2353-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | openssl-1_1 | 1.1.1l-1.2 | openSUSE-SU-2024:11127-1 |
| openSUSE Leap 15.3 | nodejs10 | 10.24.1-1.36.1 | openSUSE-SU-2021:2353-1 |
| openSUSE Leap 15.3 | nodejs12 | 12.22.2-4.16.1 | openSUSE-SU-2021:2327-1 |
| openSUSE Leap 15.2 | nodejs10 | 10.24.1-lp152.2.15.1 | openSUSE-SU-2021:1061-1 |
| openSUSE Leap 15.2 | nodejs12 | 12.22.2-lp152.3.15.1 | openSUSE-SU-2021:1059-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | openssl | 1.1.1k-r0 | — |
| Alpine v3.23 | openssl | 1.1.1k-r0 | — |
| Alpine v3.22 | openssl | 1.1.1k-r0 | — |
| Alpine v3.21 | openssl | 1.1.1k-r0 | — |
| Alpine v3.20 | openssl | 1.1.1k-r0 | — |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | openssl | 1.1.1k-r0 | — |
| Alpine v3.18 | openssl +1 | 1.1.1k-r0 | — |
| Alpine v3.17 | openssl +1 | 1.1.1k-r0 | — |
| Alpine v3.16 | openssl +1 | 1.1.1k-r0 | — |
| Alpine v3.15 | openssl +1 | 1.1.1k-r0 | — |
| Alpine v3.14 | openssl | 1.1.1k-r0 | — |
| Alpine v3.13 | openssl | 1.1.1k-r0 | — |
| Alpine v3.12 | openssl | 1.1.1k-r0 | — |
| Alpine v3.11 | openssl | 1.1.1k-r0 | — |
| Alpine v3.10 | openssl | 1.1.1k-r0 | — |
| Alpine v3.9 | openssl | 1.1.1k-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | edk2-ovmf +4 | 20200801stable-1.amzn2.0.5 | ALAS2-2024-2502 |
| Amazon Linux 2 | openssl11 +3 | 1:1.1.1g-12.amzn2.0.3 | ALAS2-2021-1622 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | openssl +3 | 1:1.1.1g-15.el8_3 | ELSA-2021-1024 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
-
dedellix/MUT-BC-SS-01 ★ 0 · Jun 23, 2026
Mutation testing on X.509 Certificate Validation IN OpenSSL v.1.1.1h, based on CVE-2021-3450.
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| crates.io | openssl-src | >= 111.11.0, < 111.15.0 | 111.15.0 | GHSA-8hfj-xrj2-pm22 |
Advisories 26
- RHSA-2021:1202 Red Hat Security Advisory: Red Hat JBoss Web Server 3.1 Service Pack 12 security update Red Hat Security Advisories (RHSA) · Oct 9, 2026
- RHSA-2021:1199 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.37 SP7 security update Red Hat Security Advisories (RHSA) · Oct 9, 2026
- RHSA-2021:1189 Red Hat Security Advisory: Red Hat Virtualization security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Oct 9, 2026
- RHSA-2021:1195 Red Hat Security Advisory: Red Hat JBoss Web Server 5.4.2 Security Update Red Hat Security Advisories (RHSA) · Oct 9, 2026
- RHSA-2021:1024 Red Hat Security Advisory: openssl security update Red Hat Security Advisories (RHSA) · Oct 9, 2026
- WID-SEC-2024-0794 Dell ECS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- WID-SEC-2025-0227 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- RLSA-2021:1024 Important: openssl security update Rocky Linux Security Advisories · Feb 5, 2026
- SUSE-SU-2021:2327-1 Security update for nodejs12 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:2353-1 Security update for nodejs10 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:2323-1 Security update for nodejs10 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:2353-1 Security update for nodejs10 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:2327-1 Security update for nodejs12 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1059-1 Security update for nodejs12 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1061-1 Security update for nodejs10 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:2326-1 Security update for nodejs12 SUSE / openSUSE Security Updates · Feb 4, 2026
- ALAS2-2024-2502 Important: edk2 security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 23, 2025
- VDE-2021-025 PHOENIX CONTACT: Security Advisory for PLCNext, ILC 2050 BI, FL MGUARD DM UNLIMITED, TC ROUTER und CLOUD CLIENT products CERT@VDE · May 14, 2025
- openSUSE-SU-2024:11127-1 libopenssl-1_1-devel-1.1.1l-1.2 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- ICSA-22-069-09 Siemens SINEC INS CISA ICS & IT advisories · May 6, 2025
- WID-SEC-2022-1303 Oracle Java SE: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jan 21, 2025
- WID-SEC-2022-0671 OpenSSL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 25, 2024
- WID-SEC-2023-0065 Oracle MySQL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 27, 2023
- SSA-389290 SSA-389290: Third-Party Component Vulnerabilities in SINEC INS Siemens ProductCERT · Mar 8, 2022
- ELSA-2021-1024 Important: openssl security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Mar 29, 2021
- ALAS2-2021-1622 Important: openssl11 security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Mar 25, 2021
References
- https://www.openssl.org/news/secadv/20210325.txt
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=2a40b7bc7b94dd7de897a74571e7024f0cf0d63b
- 20210325 Multiple Vulnerabilities in OpenSSL Affecting Cisco Products: March 2021 vendor-advisory
- [oss-security] 20210327 OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing mailing-list
- [oss-security] 20210327 Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing mailing-list
- [oss-security] 20210328 Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing mailing-list
- [oss-security] 20210328 Re: OpenSSL 1.1.1 CVE-2021-3450 CA certificate check bypass with X509_V_FLAG_X509_STRICT, CVE-2021-3449 NULL pointer deref in signature_algorithms processing mailing-list
- GLSA-202103-03 vendor-advisory
- FEDORA-2021-cbf14ab8f9 vendor-advisory
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://www.tenable.com/security/tns-2021-09
- https://security.netapp.com/advisory/ntap-20210326-0006/
- https://security.FreeBSD.org/advisories/FreeBSD-SA-21:07.openssl.asc
- https://www.tenable.com/security/tns-2021-05
- https://kc.mcafee.com/corporate/index?page=content&id=SB10356
- https://www.tenable.com/security/tns-2021-08
- https://mta.openssl.org/pipermail/openssl-announce/2021-March/000198.html
- https://www.oracle.com//security-alerts/cpujul2021.html
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0013
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- https://www.oracle.com/security-alerts/cpujul2022.html