MSRC_CVE-2026-35387

Vulnerability from csaf_microsoft - Published: 2026-04-02 00:00 - Updated: 2026-06-28 02:04
Summary
OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.
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.
CVE-2026-35387
3.1 (Low)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
CWE-670 - Always-Incorrect Control Flow Implementation
Affected products
Product Identifier Version Remediation
Unresolved product id: 21261-17084 —
Unresolved product id: 21499-17084 —
Product Identifier Version Remediation
Unresolved product id: 17084-2 —
Vendor Fix fix
Unresolved product id: 17084-3 —
None Available
Unresolved product id: 17086-4 —
None Available
Unresolved product id: 17084-1 —
Vendor Fix fix
References
To clipboard 

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "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-2026-35387 OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms. - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-35387.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 before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.",
    "tracking": {
      "current_release_date": "2026-06-28T02:04:54.000Z",
      "generator": {
        "date": "2026-06-28T08:22:25.324Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-35387",
      "initial_release_date": "2026-04-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-04-04T01:02:26.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-04-07T01:02:00.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Information published."
        },
        {
          "date": "2026-04-29T14:44:35.000Z",
          "legacy_version": "3",
          "number": "3",
          "summary": "Information published."
        },
        {
          "date": "2026-06-23T14:42:28.000Z",
          "legacy_version": "4",
          "number": "4",
          "summary": "Information published."
        },
        {
          "date": "2026-06-28T02:04:54.000Z",
          "legacy_version": "5",
          "number": "5",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "5"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              },
              {
                "category": "product_version",
                "name": "2.0",
                "product": {
                  "name": "CBL Mariner 2.0",
                  "product_id": "17086"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003cazl3 openssh 0:9.8p1-6.azl3",
                "product": {
                  "name": "\u003cazl3 openssh 0:9.8p1-6.azl3",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version",
                "name": "azl3 openssh 0:9.8p1-6.azl3",
                "product": {
                  "name": "azl3 openssh 0:9.8p1-6.azl3",
                  "product_id": "21261"
                }
              },
              {
                "category": "product_version_range",
                "name": "azl3 openssh 0:9.8p1-5.azl3",
                "product": {
                  "name": "azl3 openssh 0:9.8p1-5.azl3",
                  "product_id": "3"
                }
              },
              {
                "category": "product_version_range",
                "name": "cbl2 openssh 0:8.9p1-9.cbl2",
                "product": {
                  "name": "cbl2 openssh 0:8.9p1-9.cbl2",
                  "product_id": "4"
                }
              },
              {
                "category": "product_version_range",
                "name": "\u003cazl3 openssh 0:9.8p1-8.azl3",
                "product": {
                  "name": "\u003cazl3 openssh 0:9.8p1-8.azl3",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "azl3 openssh 0:9.8p1-8.azl3",
                "product": {
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                  "product_id": "21499"
                }
              }
            ],
            "category": "product_name",
            "name": "openssh"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003cazl3 openssh 0:9.8p1-6.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-2"
        },
        "product_reference": "2",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 openssh 0:9.8p1-6.azl3 as a component of Azure Linux 3.0",
          "product_id": "21261-17084"
        },
        "product_reference": "21261",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 openssh 0:9.8p1-5.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-3"
        },
        "product_reference": "3",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 openssh 0:8.9p1-9.cbl2 as a component of CBL Mariner 2.0",
          "product_id": "17086-4"
        },
        "product_reference": "4",
        "relates_to_product_reference": "17086"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003cazl3 openssh 0:9.8p1-8.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
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          "product_id": "21499-17084"
        },
        "product_reference": "21499",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-35387",
      "cwe": {
        "id": "CWE-670",
        "name": "Always-Incorrect Control Flow Implementation"
      },
      "notes": [
        {
          "category": "general",
          "text": "mitre",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "fixed": [
          "21261-17084",
          "21499-17084"
        ],
        "known_affected": [
          "17084-2",
          "17084-3",
          "17086-4",
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-35387 OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-35387.json"
        }
      ],
      "remediations": [
        {
          "category": "none_available",
          "date": "2026-04-04T01:02:26.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17084-3"
          ]
        },
        {
          "category": "none_available",
          "date": "2026-04-04T01:02:26.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17086-4"
          ]
        },
        {
          "category": "vendor_fix",
          "date": "2026-04-04T01:02:26.000Z",
          "details": "0:9.8p1-8.azl3:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "17084-2",
            "17084-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 3.1,
            "baseSeverity": "LOW",
            "confidentialityImpact": "NONE",
            "environmentalsScore": 0.0,
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "temporalScore": 3.1,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.1"
          },
          "products": [
            "17084-2",
            "17084-3",
            "17086-4",
            "17084-1"
          ]
        }
      ],
      "title": "OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms."
    }
  ]
}


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