Cloak AES-CTR cipher lacks ciphertext authentication, allowing chosen-plaintext forgery by bit flipping

{
  "id": "46e5ffbd7e2a2251abe4ea30ba24ce42c1f90d841d6b9d9562ccf868f954ddd9",
  "url": "https://osv.dev/vulnerability/CVE-2026-95105",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Cloak AES-CTR cipher lacks ciphertext authentication, allowing chosen-plaintext forgery by bit flipping",
    "summary": "Reliance on Obfuscation or Encryption of Security-Relevant Inputs without Integrity Checking vulnerability in danielberkompas cloak allows an attacker with write access to stored ciphertext to make it decrypt to a chosen value via bit flipping. Cloak.Ciphers.AES.CTR encrypts with AES-256 in CTR mode and stores the key tag, the IV and the ciphertext with no MAC. decrypt/2 checks only the key tag and the minimum length before it returns the plaintext, and Cloak.Ciphers.Deprecated.AES.CTR decrypts the legacy format the same way. CTR is a stream cipher, so a value XORed into the stored ciphertext is XORed into the plaintext at the same offset. An attacker who can write to the encrypted store (for example through SQL injection or a compromised replica) and who knows or can guess a stored plaintext can replace it with any value of the same length. The application receives that value with no error. This issue affects cloak: from 0.1.0-pre onward.",
    "evidence": "osv:CVE-2026-95105",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-95105",
      "aliases": [
        "CVE-2026-95105",
        "EEF-CVE-2026-95105"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/danielberkompas/cloak",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2bd17019e285b55c5c218cc842537bf9280f24c3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "fixed": "2bd17019e285b55c5c218cc842537bf9280f24c3"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-95105.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.102103844Z",
      "provider": "osv",
      "references": [
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-95105",
        "https://repo.hex.pm",
        "https://cna.erlef.org/cves/CVE-2026-95105.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/95xxx/CVE-2026-95105.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-95105",
        "https://github.com/danielberkompas/cloak/commit/2bd17019e285b55c5c218cc842537bf9280f24c3",
        "https://github.com/danielberkompas/cloak"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-649"
        ],
        "cna_assigner": "EEF",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "0.1.0-pre"
                  },
                  {
                    "fixed": "*"
                  },
                  {
                    "introduced": "2bd17019e285b55c5c218cc842537bf9280f24c3"
                  },
                  {
                    "fixed": "*"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/95xxx/CVE-2026-95105.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-95105",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 491525,
  "published_at": "2026-10-06T08:37:56.987+00:00"
}