CVE-2021-3450
mediumpriority · attend · 46EPSS 0.183 · 97 %ileexploit · PoCDEEURUUSEPSS · scored 2026-10-22
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).
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedSINEC INSsiemens_psirt
Update to V1.0.1.1 or later version
https://support.industry.siemens.com/cs/ww/en/view/109806100/ - FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Softwarecisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com - FixedSINEC INScisa_csaf_ot
Update to V1.0.1.1 or later version
https://support.industry.siemens.com/cs/ww/en/view/109806100/ - Mitigationphoenix_contact_psirt
Phoenix Contact recommends operating network-capable devices in closed networks or protected with a suitable firewall. For detailed information on our recommendations for measures to protect network-capable devices, please refer to our application note: Measures to protect network-capable devices with Ethernet connection.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.8–7.4
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (1)
Public proof-of-concept and weaponised exploit code.
affected products (118)
Products and version ranges known to be affected.
advisories (13)
Vendor and ecosystem advisories describing this.
- SSA-389290SSA-389290: Third-Party Component Vulnerabilities in SINEC INS2022-03-08csaf · siemens_psirtDE
71 vulnerabilities in third-party components as Node.js, cURL, SQLite, CivetWeb and DNS(ISC BIND) could allow an attacker to interfere with the affected product in various ways. Siemens has released an update for SINEC INS and recommends to update to the latest versions.
- VDE-2021-025PHOENIX CONTACT: Security Advisory for PLCNext, ILC 2050 BI, FL MGUARD DM UNLIMITED, TC ROUTER und CLOUD CLIENT products2021-06-23csaf · phoenix_contact_psirtDE
A Denial of Service and a CA Check Problem have been identified in multiple openSSL 1.1.1 versions, which are utilized in the Phoenix Contact products listed above.
- WID-SEC-W-2022-0671OpenSSL: Mehrere SchwachstellenDeutsch2021-03-25csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in OpenSSL ausnutzen, um einen Denial of Service Angriff durchzuführen und um kryptografische Sicherheitsmechanismen zu umgehen.
- WID-SEC-W-2022-1303Oracle Java SE: Mehrere SchwachstellenDeutsch2021-04-20csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Oracle Java SE und Oracle GraalVM ausnutzen, um die Verfügbarkeit, Vertraulichkeit und Integrität zu gefährden.
- WID-SEC-W-2023-0065Oracle MySQL: Mehrere SchwachstellenDeutsch2021-04-20csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Oracle MySQL ausnutzen, um die Verfügbarkeit, Vertraulichkeit und Integrität zu gefährden.
- WID-SEC-W-2024-0794Dell ECS: Mehrere SchwachstellenDeutsch2024-04-04csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Dell ECS ausnutzen, um seine Privilegien zu erweitern, beliebigen Programmcode mit Administratorrechten auszuführen, Informationen offenzulegen, Dateien zu manipulieren, einen Cross-Site-Scripting-Angriff durchzuführen, Sicherheitsvorkehrungen zu umgehen oder einen Denial of Service Zustand herbeizuführen.
- WID-SEC-W-2025-0227IBM QRadar SIEM: Mehrere SchwachstellenDeutsch2021-11-30csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um seine Privilegien zu erweitern, Administratorrechte zu erlangen, beliebigen Programmcode auszuführen, Informationen offenzulegen, Dateien zu manipulieren oder Sicherheitsvorkehrungen zu umgehen.
- cisco-sa-openssl-2021-GHY28dJdMultiple Vulnerabilities in OpenSSL Affecting Cisco Products: March 20212021-03-25csaf · cisco_csafUS
On March 25, 2021, the OpenSSL Project released a security advisory, OpenSSL Security Advisory [25 March 2021], ["https://www.openssl.org/news/secadv/20210325.txt"] that disclosed two vulnerabilities. Exploitation of these vulnerabilities could allow an attacker to use a valid non-certificate authority (CA) certificate to act as a CA and sign a certificate for an arbitrary organization, user or device, or to cause a denial of service (DoS) condition.
- GHSA-8hfj-xrj2-pm22Certificate check bypass in openssl-src2021-08-25ghsa · osvUS
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).
- ICSA-22-069-09Siemens SINEC INS2022-03-08icsa · cisa_csaf_otUS
71 vulnerabilities in third-party components as Node.js, cURL, SQLite, CivetWeb and DNS(ISC BIND) could allow an attacker to interfere with the affected product in various ways. Siemens has released an update for SINEC INS and recommends to update to the latest versions.
- BIT-node-2021-3450CA certificate check bypass with X509_V_FLAG_X509_STRICT2024-03-06vendor · osvUS
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).
- BIT-node-min-2021-3450CA certificate check bypass with X509_V_FLAG_X509_STRICT2024-12-16vendor · osvUS
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).
- RUSTSEC-2021-0056CA certificate check bypass with X509_V_FLAG_X509_STRICT2021-05-01vendor · osvUS
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.
also known as (8)
Other names and identifiers for this entity.
- CNNVD-202103-1456cnnvd
- EUVD-2021-1641enisa_euvd
- BDU:2021-01845fstec_bdu
- GHSA-8hfj-xrj2-pm22enisa_euvd
- BIT-node-2021-3450osv
- BIT-node-min-2021-3450osv
- GHSA-8hfj-xrj2-pm22osv
- RUSTSEC-2021-0056osv
sources
Which sources assert this record, and when.
references (150)
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2021/03/27/1cnnvd
- http://www.openwall.com/lists/oss-security/2021/03/27/2cnnvd
- http://www.openwall.com/lists/oss-security/2021/03/28/3cnnvd
- http://www.openwall.com/lists/oss-security/2021/03/28/4cnnvd
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdfcnnvd
- https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=2a40b7bc7b94dd7de897a74571e7024f0cf0d63bcnnvd
- https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=fb9fa6b51defd48157eeb207f52181f735d96148cnnvd
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44845cnnvd
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