Vulnerability-Lookup

GHSA-VR27-9W4V-HJW2

Vulnerability from github – Published: 2026-08-25 15:32 – Updated: 2026-08-25 15:32

Details

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.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-75803"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-354"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-25T13:19:29Z",
    "severity": null
  },
  "details": "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": "GHSA-vr27-9w4v-hjw2",
  "modified": "2026-08-25T15:32:59Z",
  "published": "2026-08-25T15:32:59Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-75803"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/119ab9555dc62275bbd71f6f49529b1a44feba42"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/3621257986e27e540bf96a11570929a6e5a9e05b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/6c7aa6f8f6449b7fe0137ee8be65fcd239bd7d6a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/bdeb0cd994d915342787f117ee75044f0dc36f34"
    },
    {
      "type": "WEB",
      "url": "https://github.com/openssl/openssl/commit/bf95f5f772e9362f87b25cfa2f8cb15d984865b9"
    },
    {
      "type": "WEB",
      "url": "https://openssl-library.org/news/secadv/20260825.txt"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-75803 (GCVE-0-2026-75803)

Vulnerability from cvelistv5 – Published: 2026-08-25 13:00 – Updated: 2026-08-25 13:00

Title

AEAD Forgeries with Empty Ciphertext When Using EVP_Cipher()

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.

Severity

No CVSS data available.

CWE

CWE-354 - Improper Validation of Integrity Check Value

Assigner

openssl mitre root

References

6 references

URL	Tags
https://openssl-library.org/news/secadv/20260825.txt	vendor-advisory
https://github.com/openssl/openssl/commit/6c7aa6f…	patch
https://github.com/openssl/openssl/commit/3621257…	patch
https://github.com/openssl/openssl/commit/bdeb0cd…	patch
https://github.com/openssl/openssl/commit/bf95f5f…	patch
https://github.com/openssl/openssl/commit/119ab95…	patch

Impacted products

1 product

Vendor	Product	Version
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)

Date Public

2026-08-25 15:57

Credits

Billy Brumley (Rochester Institute of Technology) Billy Brumley (Rochester Institute of Technology)

Show details on NVD website

JSON

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{
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        {
          "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"
            }
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        }
      ],
      "credits": [
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          "type": "reporter",
          "value": "Billy Brumley (Rochester Institute of Technology)"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Billy Brumley (Rochester Institute of Technology)"
        }
      ],
      "datePublic": "2026-08-25T15:57:42.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty\u003cbr\u003eciphertext can report success without verifying the supplied authentication\u003cbr\u003etag when the operation is finalized by calling the EVP_Cipher() function.\u003cbr\u003e\u003cbr\u003eImpact summary: Applications calling EVP_Cipher() on an empty ciphertext and\u003cbr\u003eexpecting the call to check the AEAD tag may accept forged messages.\u003cbr\u003e\u003cbr\u003eCWE: CWE-354 (Improper Validation of Integrity Check Value)\u003cbr\u003e\u003cbr\u003eDescription: The EVP_Cipher() API call for AEAD ciphers behaves like a one\u003cbr\u003eshot encryption and decryption call. It also verifies the AEAD tag after the\u003cbr\u003edecryption operation. However for AES-OCB and ChaCha20-Poly1305 ciphers\u003cbr\u003eit skipped the AEAD tag verification when an empty ciphertext was passed to\u003cbr\u003ethe function. The callers of this function might believe that a successful\u003cbr\u003ereturn indicates a valid AEAD tag for these ciphers, even when that has not\u003cbr\u003etruly been validated in this case.\u003cbr\u003e\u003cbr\u003eFIPS impact: no\u003cbr\u003eThe FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this CVE\u003cbr\u003eas the affected algorithms are not FIPS approved and thus not implemented\u003cbr\u003ein the FIPS module."
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      ],
      "metrics": [
        {
          "format": "other",
          "other": {
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        "shortName": "openssl"
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          "tags": [
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          "url": "https://openssl-library.org/news/secadv/20260825.txt"
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          "name": "4.0.2 git commit",
          "tags": [
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          "url": "https://github.com/openssl/openssl/commit/6c7aa6f8f6449b7fe0137ee8be65fcd239bd7d6a"
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          "name": "3.6.4 git commit",
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    "datePublished": "2026-08-25T13:00:25.067Z",
    "dateReserved": "2026-08-18T09:34:32.659Z",
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  "dataType": "CVE_RECORD",
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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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-VR27-9W4V-HJW2

CVE-2026-75803 (GCVE-0-2026-75803)

Tags

Sightings

Nomenclature