CWE-295
AllowedImproper Certificate Validation
Abstraction: Base · Status: Draft
The product does not validate, or incorrectly validates, a certificate.
2156 vulnerabilities reference this CWE, most recent first.
GHSA-C892-CWQ6-QRQF
Vulnerability from github – Published: 2023-05-26 18:30 – Updated: 2023-06-30 20:30Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-5cc8-pgp5-7mpm. This link is maintained to preserve external references.
Original Advisory
A flaw was found in Keycloak. This flaw depends on a non-default configuration "Revalidate Client Certificate" to be enabled and the reverse proxy is not validating the certificate before Keycloak. Using this method an attacker may choose the certificate which will be validated by the server. If this happens and the KC_SPI_TRUSTSTORE_FILE_FILE variable is missing/misconfigured, any trustfile may be accepted with the logging information of "Cannot validate client certificate trust: Truststore not available". This may not impact availability as the attacker would have no access to the server, but consumer applications Integrity or Confidentiality may be impacted considering a possible access to them. Considering the environment is correctly set to use "Revalidate Client Certificate" this flaw is avoidable.
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "org.keycloak:keycloak-core"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "21.1.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": true,
"github_reviewed_at": "2023-05-26T21:24:14Z",
"nvd_published_at": "2023-05-26T18:15:09Z",
"severity": "MODERATE"
},
"details": "## Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-5cc8-pgp5-7mpm. This link is maintained to preserve external references.\n\n## Original Advisory\nA flaw was found in Keycloak. This flaw depends on a non-default configuration \"Revalidate Client Certificate\" to be enabled and the reverse proxy is not validating the certificate before Keycloak. Using this method an attacker may choose the certificate which will be validated by the server. If this happens and the KC_SPI_TRUSTSTORE_FILE_FILE variable is missing/misconfigured, any trustfile may be accepted with the logging information of \"Cannot validate client certificate trust: Truststore not available\". This may not impact availability as the attacker would have no access to the server, but consumer applications Integrity or Confidentiality may be impacted considering a possible access to them. Considering the environment is correctly set to use \"Revalidate Client Certificate\" this flaw is avoidable.",
"id": "GHSA-c892-cwq6-qrqf",
"modified": "2023-06-30T20:30:22Z",
"published": "2023-05-26T18:30:21Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-1664"
},
{
"type": "WEB",
"url": "https://access.redhat.com/security/cve/CVE-2023-1664"
},
{
"type": "WEB",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2182196\u0026comment#0"
},
{
"type": "PACKAGE",
"url": "https://github.com/keycloak/keycloak"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "Duplicate Advisory: Keycloak vulnerable to untrusted certificate validation",
"withdrawn": "2023-06-30T20:30:22Z"
}
GHSA-C89C-PVM7-33WJ
Vulnerability from github – Published: 2022-05-24 17:17 – Updated: 2022-12-16 22:48Amazon EC2 Plugin connects to Windows agents via HTTPS.
Amazon EC2 Plugin 1.50.1 and earlier unconditionally accepts self-signed HTTPS certificates and does not perform hostname validation when connecting to Windows agents. This lack of validation could be abused using a man-in-the-middle attack to intercept these connections to build agents.
Amazon EC2 Plugin 1.50.2 by default no longer accepts self-signed HTTPS certificates and performs hostname validation. A new configuration option allows restoring the previous, unsafe behavior. For more information see the plugin documentation.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.50.1"
},
"package": {
"ecosystem": "Maven",
"name": "org.jenkins-ci.plugins:ec2"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.50.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2020-2187"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": true,
"github_reviewed_at": "2022-12-16T22:48:49Z",
"nvd_published_at": "2020-05-06T13:15:00Z",
"severity": "MODERATE"
},
"details": "Amazon EC2 Plugin connects to Windows agents via HTTPS.\n\nAmazon EC2 Plugin 1.50.1 and earlier unconditionally accepts self-signed HTTPS certificates and does not perform hostname validation when connecting to Windows agents. This lack of validation could be abused using a man-in-the-middle attack to intercept these connections to build agents.\n\nAmazon EC2 Plugin 1.50.2 by default no longer accepts self-signed HTTPS certificates and performs hostname validation. A new configuration option allows restoring the previous, unsafe behavior. For more information see [the plugin documentation](https://github.com/jenkinsci/ec2-plugin/#securing-the-connection-to-windows-amis).",
"id": "GHSA-c89c-pvm7-33wj",
"modified": "2022-12-16T22:48:49Z",
"published": "2022-05-24T17:17:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-2187"
},
{
"type": "WEB",
"url": "https://github.com/jenkinsci/ec2-plugin/commit/4c9f03ae202e4730fd54eda40771fa4d3873e358"
},
{
"type": "PACKAGE",
"url": "https://github.com/jenkinsci/ec2-plugin"
},
{
"type": "WEB",
"url": "https://jenkins.io/security/advisory/2020-05-06/#SECURITY-1528"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2020/05/06/3"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "Lack of SSL/TLS certificate and hostname validation in Amazon EC2 Plugin"
}
GHSA-C8GV-X3R9-Q7P4
Vulnerability from github – Published: 2025-08-28 15:30 – Updated: 2025-09-23 18:30Improper Certificate Validation in Checkmk Exchange plugin VMware vSAN allows attackers in MitM position to intercept traffic.
{
"affected": [],
"aliases": [
"CVE-2025-58126"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-28T13:16:10Z",
"severity": "MODERATE"
},
"details": "Improper Certificate Validation in Checkmk Exchange plugin VMware vSAN allows attackers in MitM position to intercept traffic.",
"id": "GHSA-c8gv-x3r9-q7p4",
"modified": "2025-09-23T18:30:21Z",
"published": "2025-08-28T15:30:42Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-58126"
},
{
"type": "WEB",
"url": "https://exchange.checkmk.com/p/vsan"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-C8X3-RG72-FWWG
Vulnerability from github – Published: 2021-09-08 20:14 – Updated: 2021-09-14 18:46HashiCorp Nomad and Nomad Enterprise Raft RPC layer allows non-server agents with a valid certificate signed by the same CA to access server-only functionality, enabling privilege escalation. Fixed in 1.0.10 and 1.1.4.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/hashicorp/nomad"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.0.10"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Go",
"name": "github.com/hashicorp/nomad"
},
"ranges": [
{
"events": [
{
"introduced": "1.1.0"
},
{
"fixed": "1.1.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2021-37218"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": true,
"github_reviewed_at": "2021-09-08T18:12:37Z",
"nvd_published_at": "2021-09-07T12:15:00Z",
"severity": "HIGH"
},
"details": "HashiCorp Nomad and Nomad Enterprise Raft RPC layer allows non-server agents with a valid certificate signed by the same CA to access server-only functionality, enabling privilege escalation. Fixed in 1.0.10 and 1.1.4.",
"id": "GHSA-c8x3-rg72-fwwg",
"modified": "2021-09-14T18:46:53Z",
"published": "2021-09-08T20:14:38Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-37218"
},
{
"type": "WEB",
"url": "https://discuss.hashicorp.com/t/hcsec-2021-21-nomad-raft-rpc-privilege-escalation/29023"
},
{
"type": "PACKAGE",
"url": "https://github.com/hashicorp/nomad"
},
{
"type": "WEB",
"url": "https://www.hashicorp.com/blog/category/nomad"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Privilege escalation in Hashicorp Nomad"
}
GHSA-C8XP-8MF3-62H9
Vulnerability from github – Published: 2021-09-07 23:02 – Updated: 2021-09-03 21:40Any CA issuer in the RPKI can trick OctoRPKI prior to https://github.com/cloudflare/cfrpki/commit/a8db4e009ef217484598ba1fd1c595b54e0f6422 into emitting an invalid VRP "MaxLength" value, causing RTR sessions to terminate.
Impact
An attacker can use this to disable RPKI Origin Validation in a victim network (for example AS 13335 - Cloudflare) prior to launching a BGP hijack which during normal operations would be rejected as "RPKI invalid". Additionally, in certain deployments RTR session flapping in and of itself also could cause BGP routing churn, causing availability issues.
Patches
https://github.com/cloudflare/cfrpki/commit/a8db4e009ef217484598ba1fd1c595b54e0f6422
https://github.com/cloudflare/cfrpki/releases/tag/v1.3.0
For more information
If you have any questions or comments about this advisory: * Email us at security@cloudflare.com
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/cloudflare/cfrpki"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.3.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2021-3761"
],
"database_specific": {
"cwe_ids": [
"CWE-295",
"CWE-787"
],
"github_reviewed": true,
"github_reviewed_at": "2021-09-03T21:40:39Z",
"nvd_published_at": "2021-09-09T14:15:00Z",
"severity": "HIGH"
},
"details": "Any CA issuer in the RPKI can trick OctoRPKI prior to https://github.com/cloudflare/cfrpki/commit/a8db4e009ef217484598ba1fd1c595b54e0f6422 into emitting an invalid VRP \"MaxLength\" value, causing RTR sessions to terminate. \n\n### Impact\n\nAn attacker can use this to disable RPKI Origin Validation in a victim network (for example AS 13335 - Cloudflare) prior to launching a BGP hijack which during normal operations would be rejected as \"RPKI invalid\". Additionally, in certain deployments RTR session flapping in and of itself also could cause BGP routing churn, causing availability issues.\n\n### Patches\nhttps://github.com/cloudflare/cfrpki/commit/a8db4e009ef217484598ba1fd1c595b54e0f6422\n\nhttps://github.com/cloudflare/cfrpki/releases/tag/v1.3.0\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Email us at [security@cloudflare.com](security@cloudflare.com)\n",
"id": "GHSA-c8xp-8mf3-62h9",
"modified": "2021-09-03T21:40:39Z",
"published": "2021-09-07T23:02:18Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/cloudflare/cfrpki/security/advisories/GHSA-c8xp-8mf3-62h9"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-3761"
},
{
"type": "WEB",
"url": "https://github.com/cloudflare/cfrpki/pull/90"
},
{
"type": "WEB",
"url": "https://github.com/cloudflare/cfrpki/commit/a8db4e009ef217484598ba1fd1c595b54e0f6422"
},
{
"type": "WEB",
"url": "https://github.com/cloudflare/cfrpki/releases/tag/v1.3.0"
},
{
"type": "WEB",
"url": "https://pkg.go.dev/vuln/GO-2022-0246"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2022/dsa-5041"
},
{
"type": "PACKAGE",
"url": "github.com/cloudflare/cfrpki"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "OctoRPKI lacks contextual out-of-bounds check when validating RPKI ROA maxLength values"
}
GHSA-C96X-RPM4-349P
Vulnerability from github – Published: 2026-04-27 21:31 – Updated: 2026-05-06 18:38When configured to use an SSL bundle, Spring Boot's Elasticsearch auto-configuration does not perform hostname verification when connecting to the Elasticsearch server.
Affected: Spring Boot 4.0.0–4.0.5; upgrade to 4.0.6 or later per vendor advisory.
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "org.springframework.boot:spring-boot-elasticsearch"
},
"ranges": [
{
"events": [
{
"introduced": "4.0.0"
},
{
"fixed": "4.0.6"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-40970"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-06T18:38:23Z",
"nvd_published_at": "2026-04-27T19:16:52Z",
"severity": "MODERATE"
},
"details": "When configured to use an SSL bundle, Spring Boot\u0027s Elasticsearch auto-configuration does not perform hostname verification when connecting to the Elasticsearch server.\n\nAffected: Spring Boot 4.0.0\u20134.0.5; upgrade to 4.0.6 or later per vendor advisory.",
"id": "GHSA-c96x-rpm4-349p",
"modified": "2026-05-06T18:38:23Z",
"published": "2026-04-27T21:31:02Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40970"
},
{
"type": "PACKAGE",
"url": "https://github.com/spring-projects/spring-boot"
},
{
"type": "WEB",
"url": "https://github.com/spring-projects/spring-boot/releases/tag/v4.0.6"
},
{
"type": "WEB",
"url": "https://spring.io/security/cve-2026-40970"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
],
"summary": "Spring Boot\u0027s Elasticsearch auto-configuration doesn\u0027t perform hostname verification when connecting to the Elasticsearch server."
}
GHSA-C9FJ-RCG9-G5CF
Vulnerability from github – Published: 2022-05-17 05:37 – Updated: 2024-02-09 03:32The Certificate Trust Policy component in Apple Mac OS X before 10.6.8 does not perform CRL checking for Extended Validation (EV) certificates that lack OCSP URLs, which might allow man-in-the-middle attackers to spoof an SSL server via a revoked certificate.
{
"affected": [],
"aliases": [
"CVE-2011-0199"
],
"database_specific": {
"cwe_ids": [
"CWE-20",
"CWE-295"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2011-06-24T20:55:00Z",
"severity": "MODERATE"
},
"details": "The Certificate Trust Policy component in Apple Mac OS X before 10.6.8 does not perform CRL checking for Extended Validation (EV) certificates that lack OCSP URLs, which might allow man-in-the-middle attackers to spoof an SSL server via a revoked certificate.",
"id": "GHSA-c9fj-rcg9-g5cf",
"modified": "2024-02-09T03:32:55Z",
"published": "2022-05-17T05:37:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2011-0199"
},
{
"type": "WEB",
"url": "http://lists.apple.com/archives/security-announce/2011//Jun/msg00000.html"
},
{
"type": "WEB",
"url": "http://support.apple.com/kb/HT4723"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/48447"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-C9P5-2JV2-63VV
Vulnerability from github – Published: 2022-05-24 19:11 – Updated: 2025-05-30 18:30On 2N Access Unit 2.0 2.31.0.40.5 devices, an attacker can pose as the web relay for a man-in-the-middle attack.
{
"affected": [],
"aliases": [
"CVE-2021-31399"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-08-13T13:15:00Z",
"severity": "MODERATE"
},
"details": "On 2N Access Unit 2.0 2.31.0.40.5 devices, an attacker can pose as the web relay for a man-in-the-middle attack.",
"id": "GHSA-c9p5-2jv2-63vv",
"modified": "2025-05-30T18:30:40Z",
"published": "2022-05-24T19:11:07Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-31399"
},
{
"type": "WEB",
"url": "https://cds.thalesgroup.com/en/tcs-cert/CVE-2021-31399"
},
{
"type": "WEB",
"url": "https://excellium-services.com/cert-xlm-advisory/cve-2021-31399"
},
{
"type": "WEB",
"url": "https://www.2n.cz/en_GB/products/ip-access-control/2n-access-unit-2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-C9XV-56CC-GJW2
Vulnerability from github – Published: 2022-05-24 19:02 – Updated: 2022-05-24 19:02An issue was discovered in Prosody before 0.11.9. The undocumented dialback_without_dialback option in mod_dialback enables an experimental feature for server-to-server authentication. It does not correctly authenticate remote server certificates, allowing a remote server to impersonate another server (when this option is enabled).
{
"affected": [],
"aliases": [
"CVE-2021-32919"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-05-13T16:15:00Z",
"severity": "HIGH"
},
"details": "An issue was discovered in Prosody before 0.11.9. The undocumented dialback_without_dialback option in mod_dialback enables an experimental feature for server-to-server authentication. It does not correctly authenticate remote server certificates, allowing a remote server to impersonate another server (when this option is enabled).",
"id": "GHSA-c9xv-56cc-gjw2",
"modified": "2022-05-24T19:02:20Z",
"published": "2022-05-24T19:02:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32919"
},
{
"type": "WEB",
"url": "https://blog.prosody.im/prosody-0.11.9-released"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/6MFFBZWXKPZEVZNQSVJNCUE7WRF3T7DG"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GUN63AHEWB2WRROJHU3BVJRWLONCT2B7"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LWJ2DG2DFJOEFEWOUN26IMYYWGSA2ZEE"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202105-15"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-4916"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2021/05/13/1"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2021/05/14/2"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-CC37-CFQH-JJWR
Vulnerability from github – Published: 2026-08-29 00:30 – Updated: 2026-08-29 00:30IBM Integrated Analytics System 1.0.0.0 through 1.0.31.0 does not validate or improperly validates TLS certificate validation, which could allow an attacker to obtain sensitive information using man in the middle techniques.
{
"affected": [],
"aliases": [
"CVE-2025-36290"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-28T22:16:45Z",
"severity": "MODERATE"
},
"details": "IBM Integrated Analytics System 1.0.0.0 through 1.0.31.0 does not validate or improperly validates TLS certificate validation, which could allow an attacker to obtain sensitive information using man in the middle techniques.",
"id": "GHSA-cc37-cfqh-jjwr",
"modified": "2026-08-29T00:30:59Z",
"published": "2026-08-29T00:30:59Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-36290"
},
{
"type": "WEB",
"url": "https://www.ibm.com/support/pages/node/7285149"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
Mitigation
Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
Mitigation
If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
CAPEC-459: Creating a Rogue Certification Authority Certificate
An adversary exploits a weakness resulting from using a hashing algorithm with weak collision resistance to generate certificate signing requests (CSR) that contain collision blocks in their "to be signed" parts. The adversary submits one CSR to be signed by a trusted certificate authority then uses the signed blob to make a second certificate appear signed by said certificate authority. Due to the hash collision, both certificates, though different, hash to the same value and so the signed blob works just as well in the second certificate. The net effect is that the adversary's second X.509 certificate, which the Certification Authority has never seen, is now signed and validated by that Certification Authority.
CAPEC-475: Signature Spoofing by Improper Validation
An adversary exploits a cryptographic weakness in the signature verification algorithm implementation to generate a valid signature without knowing the key.