FKIE_CVE-2026-75803

Vulnerability from fkie_nvd - Published: 2026-08-25 13:19 - Updated: 2026-08-25 13:19
Severity
Summary
Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty ciphertext can report success without verifying the supplied authentication tag when the operation is finalized by calling the EVP_Cipher() function. Impact summary: Applications calling EVP_Cipher() on an empty ciphertext and expecting the call to check the AEAD tag may accept forged messages. CWE: CWE-354 (Improper Validation of Integrity Check Value) Description: The EVP_Cipher() API call for AEAD ciphers behaves like a one shot encryption and decryption call. It also verifies the AEAD tag after the decryption operation. However for AES-OCB and ChaCha20-Poly1305 ciphers it skipped the AEAD tag verification when an empty ciphertext was passed to the function. The callers of this function might believe that a successful return indicates a valid AEAD tag for these ciphers, even when that has not truly been validated in this case. FIPS impact: no The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this CVE as the affected algorithms are not FIPS approved and thus not implemented in the FIPS module.
References
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/119ab9555dc62275bbd71f6f49529b1a44feba42
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/3621257986e27e540bf96a11570929a6e5a9e05b
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/6c7aa6f8f6449b7fe0137ee8be65fcd239bd7d6a
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/bdeb0cd994d915342787f117ee75044f0dc36f34
openssl-security@openssl.orghttps://github.com/openssl/openssl/commit/bf95f5f772e9362f87b25cfa2f8cb15d984865b9
openssl-security@openssl.orghttps://openssl-library.org/news/secadv/20260825.txt
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "OpenSSL",
          "vendor": "OpenSSL",
          "versions": [
            {
              "lessThan": "4.0.2",
              "status": "affected",
              "version": "4.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.6.4",
              "status": "affected",
              "version": "3.6.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.5.8",
              "status": "affected",
              "version": "3.5.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.4.7",
              "status": "affected",
              "version": "3.4.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.0.22",
              "status": "affected",
              "version": "3.0.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "openssl-security@openssl.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty\nciphertext can report success without verifying the supplied authentication\ntag when the operation is finalized by calling the EVP_Cipher() function.\n\nImpact summary: Applications calling EVP_Cipher() on an empty ciphertext and\nexpecting the call to check the AEAD tag may accept forged messages.\n\nCWE: CWE-354 (Improper Validation of Integrity Check Value)\n\nDescription: The EVP_Cipher() API call for AEAD ciphers behaves like a one\nshot encryption and decryption call. It also verifies the AEAD tag after the\ndecryption operation. However for AES-OCB and ChaCha20-Poly1305 ciphers\nit skipped the AEAD tag verification when an empty ciphertext was passed to\nthe function. The callers of this function might believe that a successful\nreturn indicates a valid AEAD tag for these ciphers, even when that has not\ntruly been validated in this case.\n\nFIPS impact: no\nThe FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this CVE\nas the affected algorithms are not FIPS approved and thus not implemented\nin the FIPS module."
    }
  ],
  "id": "CVE-2026-75803",
  "lastModified": "2026-08-25T13:19:29.570",
  "metrics": {},
  "published": "2026-08-25T13:19:29.570",
  "references": [
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/119ab9555dc62275bbd71f6f49529b1a44feba42"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/3621257986e27e540bf96a11570929a6e5a9e05b"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/6c7aa6f8f6449b7fe0137ee8be65fcd239bd7d6a"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/bdeb0cd994d915342787f117ee75044f0dc36f34"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://github.com/openssl/openssl/commit/bf95f5f772e9362f87b25cfa2f8cb15d984865b9"
    },
    {
      "source": "openssl-security@openssl.org",
      "url": "https://openssl-library.org/news/secadv/20260825.txt"
    }
  ],
  "sourceIdentifier": "openssl-security@openssl.org",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-354"
        }
      ],
      "source": "openssl-security@openssl.org",
      "type": "Secondary"
    }
  ]
}



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