FKIE_CVE-2026-31790

Vulnerability from fkie_nvd - Published: 2026-04-07 22:16 - Updated: 2026-04-23 15:39
Summary
Issue summary: Applications using RSASVE key encapsulation to establish a secret encryption key can send contents of an uninitialized memory buffer to a malicious peer. Impact summary: The uninitialized buffer might contain sensitive data from the previous execution of the application process which leads to sensitive data leakage to an attacker. RSA_public_encrypt() returns the number of bytes written on success and -1 on error. The affected code tests only whether the return value is non-zero. As a result, if RSA encryption fails, encapsulation can still return success to the caller, set the output lengths, and leave the caller to use the contents of the ciphertext buffer as if a valid KEM ciphertext had been produced. If applications use EVP_PKEY_encapsulate() with RSA/RSASVE on an attacker-supplied invalid RSA public key without first validating that key, then this may cause stale or uninitialized contents of the caller-provided ciphertext buffer to be disclosed to the attacker in place of the KEM ciphertext. As a workaround calling EVP_PKEY_public_check() or EVP_PKEY_public_check_quick() before EVP_PKEY_encapsulate() will mitigate the issue. The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.1 and 3.0 are affected by this issue.
Impacted products

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "B28A8143-89A4-4332-A1F8-A65FB5AA829F",
              "versionEndExcluding": "3.0.20",
              "versionStartIncluding": "3.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "CF303B21-D9BF-461D-B7B0-A3FE1D557A9F",
              "versionEndExcluding": "3.3.7",
              "versionStartIncluding": "3.3.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "DCCE43D0-8F17-475D-9EE6-842F758A9905",
              "versionEndExcluding": "3.4.5",
              "versionStartIncluding": "3.4.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "F6BC0271-444D-4597-BF05-DC60034EAA49",
              "versionEndExcluding": "3.5.6",
              "versionStartIncluding": "3.5.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "4A9E621D-29D8-418A-BF37-BED333C14507",
              "versionEndExcluding": "3.6.2",
              "versionStartIncluding": "3.6.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Issue summary: Applications using RSASVE key encapsulation to establish\na secret encryption key can send contents of an uninitialized memory buffer to\na malicious peer.\n\nImpact summary: The uninitialized buffer might contain sensitive data from the\nprevious execution of the application process which leads to sensitive data\nleakage to an attacker.\n\nRSA_public_encrypt() returns the number of bytes written on success and -1\non error. The affected code tests only whether the return value is non-zero.\nAs a result, if RSA encryption fails, encapsulation can still return success to\nthe caller, set the output lengths, and leave the caller to use the contents of\nthe ciphertext buffer as if a valid KEM ciphertext had been produced.\n\nIf applications use EVP_PKEY_encapsulate() with RSA/RSASVE on an\nattacker-supplied invalid RSA public key without first validating that key,\nthen this may cause stale or uninitialized contents of the caller-provided\nciphertext buffer to be disclosed to the attacker in place of the KEM\nciphertext.\n\nAs a workaround calling EVP_PKEY_public_check() or\nEVP_PKEY_public_check_quick() before EVP_PKEY_encapsulate() will mitigate\nthe issue.\n\nThe FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.1 and 3.0 are affected by this issue."
    }
  ],
  "id": "CVE-2026-31790",
  "lastModified": "2026-04-23T15:39:44.033",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-04-07T22:16:21.770",
  "references": [
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/001e01db3e996e13ffc72386fe79d03a6683b5ac"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/abd8b2eec7e3f3fda60ecfb68498b246b52af482"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/b922e24e5b23ffb9cb9e14cadff23d91e9f7e406"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/d5f8e71cd0a54e961d0c3b174348f8308486f790"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/openssl/openssl/commit/eed200f58cd8645ed77e46b7e9f764e284df379e"
    },
    {
      "source": "openssl-security@openssl.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://openssl-library.org/news/secadv/20260407.txt"
    }
  ],
  "sourceIdentifier": "openssl-security@openssl.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-754"
        }
      ],
      "source": "openssl-security@openssl.org",
      "type": "Secondary"
    }
  ]
}


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