CVE-2026-63076 (GCVE-0-2026-63076)

Vulnerability from cvelistv5 – Published: 2026-08-25 13:00 – Updated: 2026-08-25 14:37
VLAI
Title
Invalid Pointer Dereference in CMP Server via Crafted protectionAlg
Summary
Issue summary: OpenSSL CMP password based protection verification only checks whether the protectionAlg parameter was not NULL and not its ASN.1 type, before treating it as a PBMParameter. A crafted message can contain a parameter of a different type, which is then dereferenced as an invalid pointer. Impact summary: A remote, unauthenticated attacker can crash an application acting as a CMP server that accepts PBM-protected messages, or a CMP client talking to a malicious or intercepted CMP server, resulting in a Denial of Service. CWE: CWE-476: NULL Pointer Dereference Description: When verifying the password-based MAC protection of a CMP message, OpenSSL library reads the protectionAlg algorithm parameter with X509_ALGOR_get0(), which returns both the parameter type and its value pointer. The value is then cast to an ASN1_STRING and treated as the expected PBMParameter after only checking that pointer is not NULL. The parameter type returned by X509_ALGOR_get0() was never consulted. This happens during protection verification, before any MAC is computed, so no knowledge of the PBM shared secret is required; the only precondition is that PBM verification is reachable. On the server side this is reached from OSSL_CMP_SRV_process_request() for any application that stands up a CMP server accepting PBM-protected messages, and on the client side from CMP response validation against a malicious or on-path (MITM) server. The reliable consequence is a denial of service; there is no memory disclosure, no controlled memory write, and no path to code execution. CMP is a specialized feature that an application must explicitly enable. FIPS impact: no As the CMP code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-25 14:37 UTC
CWE
  • CWE-476 - NULL Pointer Dereference
Assigner
openssl CNA under the mitre root
CNA scorecard B 78/100 over 43 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
OpenSSL OpenSSL Affected: 4.0.0 , < 4.0.2 (semver)
Affected: 3.6.0 , < 3.6.4 (semver)
Affected: 3.5.0 , < 3.5.8 (semver)
Affected: 3.4.0 , < 3.4.7 (semver)
Affected: 3.0.0 , < 3.0.22 (semver)
guessed Create a notification for this product.
Date Public
2026-08-25 11:36
Credits
Ying Dong Bhabani Sankar Das Daniel Kubec
Show details on NVD website
To clipboard 

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                  "versionType": "semver"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "reporter",
              "value": "Ying Dong"
            },
            {
              "lang": "en",
              "type": "reporter",
              "value": "Bhabani Sankar Das"
            },
            {
              "lang": "en",
              "type": "remediation developer",
              "value": "Daniel Kubec"
            }
          ],
          "datePublic": "2026-08-25T11:36:16.000Z",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "Issue summary: OpenSSL CMP password based protection verification only\u003cbr\u003echecks whether the protectionAlg parameter was not NULL and not its\u003cbr\u003eASN.1 type, before treating it as a PBMParameter. A crafted message can\u003cbr\u003econtain a parameter of a different type, which is then dereferenced as an\u003cbr\u003einvalid pointer.\u003cbr\u003e\u003cbr\u003eImpact summary: A remote, unauthenticated attacker can crash an application\u003cbr\u003eacting as a CMP server that accepts PBM-protected messages, or a CMP client\u003cbr\u003etalking to a malicious or intercepted CMP server, resulting in a Denial of\u003cbr\u003eService.\u003cbr\u003e\u003cbr\u003eCWE: CWE-476: NULL Pointer Dereference\u003cbr\u003e\u003cbr\u003eDescription: When verifying the password-based MAC protection of a CMP\u003cbr\u003emessage, OpenSSL library reads the protectionAlg algorithm parameter with\u003cbr\u003eX509_ALGOR_get0(), which returns both the parameter type and its value\u003cbr\u003epointer. The value is then cast to an ASN1_STRING and treated as the\u003cbr\u003eexpected PBMParameter after only checking that pointer is not NULL. The\u003cbr\u003eparameter type returned by X509_ALGOR_get0() was never consulted.\u003cbr\u003e\u003cbr\u003eThis happens during protection verification, before any MAC is computed, so\u003cbr\u003eno knowledge of the PBM shared secret is required; the only precondition is\u003cbr\u003ethat PBM verification is reachable. On the server side this is reached from\u003cbr\u003eOSSL_CMP_SRV_process_request() for any application that stands up a CMP\u003cbr\u003eserver accepting PBM-protected messages, and on the client side from CMP\u003cbr\u003eresponse validation against a malicious or on-path (MITM) server. The\u003cbr\u003ereliable consequence is a denial of service; there is no memory disclosure,\u003cbr\u003eno controlled memory write, and no path to code execution. CMP is a\u003cbr\u003especialized feature that an application must explicitly enable.\u003cbr\u003e\u003cbr\u003eFIPS impact: no\u003cbr\u003eAs the CMP code lives outside the FIPS module boundary, no FIPS modules\u003cbr\u003eare affected by this CVE."
                }
              ],
              "value": "Issue summary: OpenSSL CMP password based protection verification only\nchecks whether the protectionAlg parameter was not NULL and not its\nASN.1 type, before treating it as a PBMParameter. A crafted message can\ncontain a parameter of a different type, which is then dereferenced as an\ninvalid pointer.\n\nImpact summary: A remote, unauthenticated attacker can crash an application\nacting as a CMP server that accepts PBM-protected messages, or a CMP client\ntalking to a malicious or intercepted CMP server, resulting in a Denial of\nService.\n\nCWE: CWE-476: NULL Pointer Dereference\n\nDescription: When verifying the password-based MAC protection of a CMP\nmessage, OpenSSL library reads the protectionAlg algorithm parameter with\nX509_ALGOR_get0(), which returns both the parameter type and its value\npointer. The value is then cast to an ASN1_STRING and treated as the\nexpected PBMParameter after only checking that pointer is not NULL. The\nparameter type returned by X509_ALGOR_get0() was never consulted.\n\nThis happens during protection verification, before any MAC is computed, so\nno knowledge of the PBM shared secret is required; the only precondition is\nthat PBM verification is reachable. On the server side this is reached from\nOSSL_CMP_SRV_process_request() for any application that stands up a CMP\nserver accepting PBM-protected messages, and on the client side from CMP\nresponse validation against a malicious or on-path (MITM) server. The\nreliable consequence is a denial of service; there is no memory disclosure,\nno controlled memory write, and no path to code execution. CMP is a\nspecialized feature that an application must explicitly enable.\n\nFIPS impact: no\nAs the CMP code lives outside the FIPS module boundary, no FIPS modules\nare affected by this CVE."
            }
          ],
          "metrics": [
            {
              "format": "other",
              "other": {
                "content": {
                  "text": "Moderate"
                },
                "type": "https://openssl-library.org/policies/general/security-policy/"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-476",
                  "description": "CWE-476 NULL Pointer Dereference",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-25T13:00:11.218Z",
            "orgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
            "shortName": "openssl"
          },
          "references": [
            {
              "name": "OpenSSL Advisory",
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://openssl-library.org/news/secadv/20260825.txt"
            },
            {
              "name": "4.0.2 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/a17cc8d612ecff6d94a9b7ca8b5283ddf5ff570e"
            },
            {
              "name": "3.6.4 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/a7af46a92d0ce19a90e669ef56d2576a07924226"
            },
            {
              "name": "3.5.8 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/cdacfff557389abfa9e4615abded2ec984517d6c"
            },
            {
              "name": "3.4.7 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/a1f348ccb328c3afbd4ba6883f9b7c813c043259"
            },
            {
              "name": "3.0.22 git commit",
              "tags": [
                "patch"
              ],
              "url": "https://github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "Invalid Pointer Dereference in CMP Server via Crafted protectionAlg",
          "x_generator": {
            "engine": "Vulnogram 0.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "3a12439a-ef3a-4c79-92e6-6081a721f1e5",
        "assignerShortName": "openssl",
        "cveId": "CVE-2026-63076",
        "datePublished": "2026-08-25T13:00:11.218Z",
        "dateReserved": "2026-07-15T13:10:26.188Z",
        "dateUpdated": "2026-08-25T14:37:32.193Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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