Vulnerability-Lookup

GHSA-7PHF-QPM5-Q6P3

Vulnerability from github – Published: 2026-06-09 18:30 – Updated: 2026-06-10 09:31

Details

Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers.

AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, EVP_DecryptFinal_ex() is documented to return success only if the tag is verified succesfully.

In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls EVP_DecryptFinal_ex() without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value.

When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key.

AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2.

No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as these algorithms are not FIPS approved and the affected code is outside the OpenSSL FIPS module boundary.

Severity

4.8 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-45446"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-325"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-09T17:17:19Z",
    "severity": "MODERATE"
  },
  "details": "Issue summary: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV\n(RFC 8452) mishandle the authentication of AAD (Additional Authenticated\nData) with an empty ciphertext allowing a forgery of such messages.\n\nImpact summary: An attacker can forge empty messages with arbitrary AAD\nto the victim\u0027s application using these ciphers.\n\nAES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD\nmodes: they accept a key, nonce, optional AAD (bytes that are authenticated\nbut not encrypted), and plaintext, and produces ciphertext plus a 16-byte\ntag. On decrypt, `EVP_DecryptFinal_ex()` is documented to return success only\nif the tag is verified succesfully.\n\nIn OpenSSL\u0027s provider implementation of these ciphers, the expected tag is\ncomputed only when decryption function is invoked with non-empty data.\nIf the caller supplies AAD and then calls `EVP_DecryptFinal_ex()` without\ninvocation of the ciphertext update, which can happen when the received\nciphertext length is zero, the tag is never recalculated and still holds its\nall-zeros value.\n\nWhen AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty\nciphertext, and all-zeros tag passes authentication under any key they do not\nknow, single-shot. When AES-SIV is used, for mounting the attack it\u0027s\nnecessary for the application to reuse the decryption context without\nresetting the key.\n\nAES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since\nOpenSSL 3.2.\n\nNo protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support\neither AES-GCM-SIV or AES-SIV. To mount an attack, the applications must\nimplement their own protocol and use the EVP interface. Also they must skip the\nciphertext update when a message with an empty ciphertext arrives.\n\nThe FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this\nissue, as these algorithms are not FIPS approved and the affected code is\noutside the OpenSSL FIPS module boundary.",
  "id": "GHSA-7phf-qpm5-q6p3",
  "modified": "2026-06-10T09:31:57Z",
  "published": "2026-06-09T18:30:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45446"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/25b32cd9d41d2bc01b6abc425bb4baf2c2236fdc"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/71e2a5d263518cf5866043bd60ee4994d59e53a3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/7fe3f33a3b3a4c487aa4dcdbc87057f66ffd2b85"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/daca0f48e4a69a2892a62262bad59e62a8a76598"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/eec5e9bf0d867333b8495e456f5235d225798a68"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/security/commit/25b32cd9d41d2bc01b6abc425bb4baf2c2236fdc"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/security/commit/71e2a5d263518cf5866043bd60ee4994d59e53a3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/security/commit/7fe3f33a3b3a4c487aa4dcdbc87057f66ffd2b85"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/security/commit/daca0f48e4a69a2892a62262bad59e62a8a76598"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/security/commit/eec5e9bf0d867333b8495e456f5235d225798a68"
    },
    {
      "type": "WEB",
      "url": "https://openssl-library.org/news/secadv/20260609.txt"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-45446 (GCVE-0-2026-45446)

Vulnerability from cvelistv5 – Published: 2026-06-09 16:03 – Updated: 2026-06-10 07:48

Title

Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes

Summary

Issue summary: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages. Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers. AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, `EVP_DecryptFinal_ex()` is documented to return success only if the tag is verified succesfully. In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls `EVP_DecryptFinal_ex()` without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value. When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key. AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2. No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as these algorithms are not FIPS approved and the affected code is outside the OpenSSL FIPS module boundary.

Severity

4.8 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-325 - Missing Cryptographic Step

Assigner

openssl

References

6 references

URL	Tags
https://openssl-library.org/news/secadv/20260609.txt	vendor-advisory
https://github.com/openssl/openssl/commit/25b32cd…	patch
https://github.com/openssl/openssl/commit/eec5e9b…	patch
https://github.com/openssl/openssl/commit/7fe3f33…	patch
https://github.com/openssl/openssl/commit/daca0f4…	patch
https://github.com/openssl/openssl/commit/71e2a5d…	patch

Impacted products

1 product

Vendor	Product	Version
OpenSSL	OpenSSL	Affected: 4.0.0 , < 4.0.1 (semver) Affected: 3.6.0 , < 3.6.3 (semver) Affected: 3.5.0 , < 3.5.7 (semver) Affected: 3.4.0 , < 3.4.6 (semver) Affected: 3.0.0 , < 3.0.21 (semver)

Date Public

2026-06-09 14:00

Credits

Alex Gaynor (Anthropic) Dmitry Belyavskiy (Red Hat)

Show details on NVD website

JSON

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{
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    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "HIGH",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 4.8,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "LOW",
              "integrityImpact": "LOW",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-45446",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
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                "role": "CISA Coordinator",
                "timestamp": "2026-06-09T18:48:41.903041Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-09T18:49:07.756Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "OpenSSL",
          "vendor": "OpenSSL",
          "versions": [
            {
              "lessThan": "4.0.1",
              "status": "affected",
              "version": "4.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.6.3",
              "status": "affected",
              "version": "3.6.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.5.7",
              "status": "affected",
              "version": "3.5.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.4.6",
              "status": "affected",
              "version": "3.4.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.0.21",
              "status": "affected",
              "version": "3.0.0",
              "versionType": "semver"
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          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Alex Gaynor (Anthropic)"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Dmitry Belyavskiy (Red Hat)"
        }
      ],
      "datePublic": "2026-06-09T14:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Issue summary: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV\u003cbr\u003e(RFC 8452) mishandle the authentication of AAD (Additional Authenticated\u003cbr\u003eData) with an empty ciphertext allowing a forgery of such messages.\u003cbr\u003e\u003cbr\u003eImpact summary: An attacker can forge empty messages with arbitrary AAD\u003cbr\u003eto the victim\u0027s application using these ciphers.\u003cbr\u003e\u003cbr\u003eAES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD\u003cbr\u003emodes: they accept a key, nonce, optional AAD (bytes that are authenticated\u003cbr\u003ebut not encrypted), and plaintext, and produces ciphertext plus a 16-byte\u003cbr\u003etag. On decrypt, `EVP_DecryptFinal_ex()` is documented to return success only\u003cbr\u003eif the tag is verified succesfully.\u003cbr\u003e\u003cbr\u003eIn OpenSSL\u0027s provider implementation of these ciphers, the expected tag is\u003cbr\u003ecomputed only when decryption function is invoked with non-empty data.\u003cbr\u003eIf the caller supplies AAD and then calls `EVP_DecryptFinal_ex()` without\u003cbr\u003einvocation of the ciphertext update, which can happen when the received\u003cbr\u003eciphertext length is zero, the tag is never recalculated and still holds its\u003cbr\u003eall-zeros value.\u003cbr\u003e\u003cbr\u003eWhen AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty\u003cbr\u003eciphertext, and all-zeros tag passes authentication under any key they do not\u003cbr\u003eknow, single-shot. When AES-SIV is used, for mounting the attack it\u0027s\u003cbr\u003enecessary for the application to reuse the decryption context without\u003cbr\u003eresetting the key.\u003cbr\u003e\u003cbr\u003eAES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since\u003cbr\u003eOpenSSL 3.2.\u003cbr\u003e\u003cbr\u003eNo protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support\u003cbr\u003eeither AES-GCM-SIV or AES-SIV. To mount an attack, the applications must\u003cbr\u003eimplement their own protocol and use the EVP interface. Also they must skip the\u003cbr\u003eciphertext update when a message with an empty ciphertext arrives.\u003cbr\u003e\u003cbr\u003eThe FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this\u003cbr\u003eissue, as these algorithms are not FIPS approved and the affected code is\u003cbr\u003eoutside the OpenSSL FIPS module boundary."
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        }
      ],
      "metrics": [
        {
          "format": "other",
          "other": {
            "content": {
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            },
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        }
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          "url": "https://openssl-library.org/news/secadv/20260609.txt"
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        }
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-7PHF-QPM5-Q6P3

CVE-2026-45446 (GCVE-0-2026-45446)

Tags

Sightings

Nomenclature