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UBUNTU-CVE-2026-63073 (CVE-2026-63073)

Vulnerability from osv_ubuntu – Published: 2026-08-25 00:00 – Updated: 2026-09-16 11:36 – Source website
VLAI
Details

Issue summary: OpenSSL CMP response validation passed an unexpected response sender distinguished name directly as the format string to ERR_raise_data(). Impact summary: A malicious or intercepted CMP endpoint can crash a CMP client that enforces an expected sender or uses a pinned server certificate whose subject becomes the default expected sender. CWE: CWE-134 (Use of Externally-Controlled Format String) Description: When validating a received CMP message, ossl_cmp_msg_check_update() converts the peer-supplied sender distinguished name with X509_NAME_oneline() and passes it directly as the format argument to ERR_raise_data(). Percent characters survive the conversion, so a sender DN such as "CN=%s%n" reaches BIO_vsnprintf() as an attacker-controlled format string with no matching variadic arguments. This path is only reached when the caller configures an expected sender or pins a server certificate, which is the normal configuration for a CMP client validating server responses. Since the attacker controls the format string but none of the variadic arguments, such specifiers as %s and %n dereference or write through unrelated stack contents and crash the client. The reliable consequence is a denial of service, when the response comes from a malicious or intercepted CMP endpoint. There is no controlled memory write, arbitrary-address read, or reliable path to remote code execution. FIPS impact: no No FIPS modules are affected by this issue, as the CMP protocol implementation is outside the OpenSSL FIPS module boundary.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
N/A (UNKNOWN)
low
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nodejs",
            "binary_version": "4.2.6~dfsg-1ubuntu4.2+esm3"
          },
          {
            "binary_name": "nodejs-legacy",
            "binary_version": "4.2.6~dfsg-1ubuntu4.2+esm3"
          }
        ],
        "priority_reason": "OpenSSL developers have rated this low severity"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "nodejs",
        "purl": "pkg:deb/ubuntu/nodejs@4.2.6~dfsg-1ubuntu4.2+esm3?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.10.25~dfsg2-2ubuntu1",
        "4.2.2~dfsg-1",
        "4.2.3~dfsg-1",
        "4.2.4~dfsg-1ubuntu1",
        "4.2.4~dfsg-2",
        "4.2.6~dfsg-1ubuntu1",
        "4.2.6~dfsg-1ubuntu4",
        "4.2.6~dfsg-1ubuntu4.1",
        "4.2.6~dfsg-1ubuntu4.2",
        "4.2.6~dfsg-1ubuntu4.2+esm1",
        "4.2.6~dfsg-1ubuntu4.2+esm2",
        "4.2.6~dfsg-1ubuntu4.2+esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nodejs",
            "binary_version": "8.10.0~dfsg-2ubuntu0.4+esm6"
          }
        ],
        "priority_reason": "OpenSSL developers have rated this low severity"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "nodejs",
        "purl": "pkg:deb/ubuntu/nodejs@8.10.0~dfsg-2ubuntu0.4+esm6?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "6.11.4~dfsg-1ubuntu1",
        "6.11.4~dfsg-1ubuntu2",
        "6.12.0~dfsg-1ubuntu1",
        "6.12.0~dfsg-2ubuntu1",
        "6.12.0~dfsg-2ubuntu2",
        "8.10.0~dfsg-2",
        "8.10.0~dfsg-2ubuntu0.2",
        "8.10.0~dfsg-2ubuntu0.3",
        "8.10.0~dfsg-2ubuntu0.4",
        "8.10.0~dfsg-2ubuntu0.4+esm1",
        "8.10.0~dfsg-2ubuntu0.4+esm2",
        "8.10.0~dfsg-2ubuntu0.4+esm3",
        "8.10.0~dfsg-2ubuntu0.4+esm4",
        "8.10.0~dfsg-2ubuntu0.4+esm5",
        "8.10.0~dfsg-2ubuntu0.4+esm6"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "efi-shell-aa64",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "efi-shell-loongarch64",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "efi-shell-riscv64",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "efi-shell-x64",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "ovmf",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "ovmf-amdsev",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "ovmf-generic",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "ovmf-inteltdx",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "ovmf-legacy",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "qemu-efi-aarch64",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "qemu-efi-loongarch64",
            "binary_version": "2025.11-3ubuntu7.2"
          },
          {
            "binary_name": "qemu-efi-riscv64",
            "binary_version": "2025.11-3ubuntu7.2"
          }
        ],
        "priority_reason": "OpenSSL developers have rated this low severity"
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "edk2",
        "purl": "pkg:deb/ubuntu/edk2@2025.11-3ubuntu7.2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2025.02-8ubuntu3",
        "2025.11-3ubuntu6",
        "2025.11-3ubuntu7",
        "2025.11-3ubuntu7.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "efi-shell-aa64-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "efi-shell-loongarch64-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "efi-shell-riscv64-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "efi-shell-x64-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "ovmf-amdsev-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "ovmf-generic-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "ovmf-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "ovmf-inteltdx-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "ovmf-legacy-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "qemu-efi-aarch64-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "qemu-efi-loongarch64-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          },
          {
            "binary_name": "qemu-efi-riscv64-hwe",
            "binary_version": "2025.11-3ubuntu8.2"
          }
        ],
        "priority_reason": "OpenSSL developers have rated this low severity"
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "edk2-hwe",
        "purl": "pkg:deb/ubuntu/edk2-hwe@2025.11-3ubuntu8.2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2025.11-3ubuntu6",
        "2025.11-3ubuntu8",
        "2025.11-3ubuntu8.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libssl3t64",
            "binary_version": "3.5.5-1ubuntu3.4"
          },
          {
            "binary_name": "openssl",
            "binary_version": "3.5.5-1ubuntu3.4"
          },
          {
            "binary_name": "openssl-provider-legacy",
            "binary_version": "3.5.5-1ubuntu3.4"
          }
        ],
        "priority_reason": "OpenSSL developers have rated this low severity"
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "openssl",
        "purl": "pkg:deb/ubuntu/openssl@3.5.5-1ubuntu3.4?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.5.5-1ubuntu3.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.5.3-1ubuntu2",
        "3.5.5-1ubuntu1",
        "3.5.5-1ubuntu3",
        "3.5.5-1ubuntu3.2",
        "3.5.5-1ubuntu3.3"
      ]
    }
  ],
  "aliases": [],
  "details": "Issue summary: OpenSSL CMP response validation passed an unexpected response sender distinguished name directly as the format string to `ERR_raise_data()`. Impact summary: A malicious or intercepted CMP endpoint can crash a CMP client that enforces an expected sender or uses a pinned server certificate whose subject becomes the default expected sender. CWE: CWE-134 (Use of Externally-Controlled Format String) Description: When validating a received CMP message, ossl_cmp_msg_check_update() converts the peer-supplied sender distinguished name with X509_NAME_oneline() and passes it directly as the format argument to ERR_raise_data(). Percent characters survive the conversion, so a sender DN such as \"CN=%s%n\" reaches BIO_vsnprintf() as an attacker-controlled format string with no matching variadic arguments. This path is only reached when the caller configures an expected sender or pins a server certificate, which is the normal configuration for a CMP client validating server responses. Since the attacker controls the format string but none of the variadic arguments, such specifiers as %s and %n dereference or write through unrelated stack contents and crash the client. The reliable consequence is a denial of service, when the response comes from a malicious or intercepted CMP endpoint. There is no controlled memory write, arbitrary-address read, or reliable path to remote code execution. FIPS impact: no No FIPS modules are affected by this issue, as the CMP protocol implementation is outside the OpenSSL FIPS module boundary.",
  "id": "UBUNTU-CVE-2026-63073",
  "modified": "2026-09-16T11:36:44Z",
  "published": "2026-08-25T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-63073"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-63073"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8678-1"
    }
  ],
  "related": [
    "USN-8678-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "low",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-63073"
  ]
}



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