MSRC_CVE-2023-25136

Vulnerability from csaf_microsoft - Published: 2023-02-01 00:00 - Updated: 2025-10-01 23:11
Summary
OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states "remote code execution is theoretically possible."

Notes

Additional Resources
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer
The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
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{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
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    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2023-25136 OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states \"remote code execution is theoretically possible.\" - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2023/msrc_cve-2023-25136.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states \"remote code execution is theoretically possible.\"",
    "tracking": {
      "current_release_date": "2025-10-01T23:11:30.000Z",
      "generator": {
        "date": "2025-10-20T00:15:36.620Z",
        "engine": {
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      "revision_history": [
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          "summary": "Information published."
        }
      ],
      "status": "final",
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  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "1.0",
                "product": {
                  "name": "CBL Mariner 1.0",
                  "product_id": "16820"
                }
              },
              {
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            ],
            "category": "product_name",
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          },
          {
            "branches": [
              {
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                "product": {
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              },
              {
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                "name": "cm1 openssh 8.9p1-3",
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              },
              {
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                "name": "\u003ccbl2 openssh 8.9p1-8",
                "product": {
                  "name": "\u003ccbl2 openssh 8.9p1-8",
                  "product_id": "1"
                }
              },
              {
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                "name": "cbl2 openssh 8.9p1-8",
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            ],
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      {
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  },
  "vulnerabilities": [
    {
      "cve": "CVE-2023-25136",
      "cwe": {
        "id": "CWE-415",
        "name": "Double Free"
      },
      "notes": [
        {
          "category": "general",
          "text": "mitre",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
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          "17996-17086"
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        "known_affected": [
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          "17086-1"
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      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2023-25136 OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states \"remote code execution is theoretically possible.\" - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2023/msrc_cve-2023-25136.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2025-10-01T23:11:30.000Z",
          "details": "8.9p1-3:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "16820-2"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        },
        {
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          "date": "2025-10-01T23:11:30.000Z",
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          "product_ids": [
            "17086-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "environmentalsScore": 0.0,
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "temporalScore": 6.5,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H",
            "version": "3.1"
          },
          "products": [
            "16820-2",
            "17086-1"
          ]
        }
      ],
      "title": "OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states \"remote code execution is theoretically possible.\""
    }
  ]
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.