Vulnerability-Lookup

CVE-2025-65849 (GCVE-0-2025-65849)

Vulnerability from cvelistv5 – Published: 2025-12-08 00:00 – Updated: 2025-12-11 14:36 Disputed

Summary

A cryptanalytic break in Altcha Proof-of-Work obfuscation mode version 0.8.0 and later allows for remote visitors to recover the Proof-of-Work nonce in constant time via mathematical deduction. NOTE: this is disputed by the Supplier because the product's objective is "to discourage automated scraping / bots, not guarantee resistance to determined attackers." The documentation states “the goal is not to provide a secure cryptographic algorithm but to use a proof-of-work mechanism that allows any capable device to decrypt the hidden data.”

Severity

9.1 (Critical)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-12-09 20:01 UTC

CWE

n/a
CWE-327 - Use of a Broken or Risky Cryptographic Algorithm

Assigner

mitre CNA under the mitre root

CNA scorecard E 28/100 over 2263 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/altcha-org/altcha/blob/154f874…
https://altcha.org/docs/v2/obfuscation/
https://github.com/eternal-flame-AD/altcha-deobfs

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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      {
        "metrics": [
          {
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              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
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              "baseScore": 9.1,
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              "confidentialityImpact": "HIGH",
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              "privilegesRequired": "NONE",
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
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          "lang": "en",
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          "url": "https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194"
        },
        {
          "url": "https://altcha.org/docs/v2/obfuscation/"
        },
        {
          "url": "https://github.com/eternal-flame-AD/altcha-deobfs"
        }
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            "value": "A cryptanalytic break in Altcha Proof-of-Work obfuscation mode version 0.8.0 and later allows for remote visitors to recover the Proof-of-Work nonce in constant time via mathematical deduction. NOTE: this is disputed by the Supplier because the product\u0027s objective is \"to discourage automated scraping / bots, not guarantee resistance to determined attackers.\" The documentation states \u201cthe goal is not to provide a secure cryptographic algorithm but to use a proof-of-work mechanism that allows any capable device to decrypt the hidden data.\u201d"
          },
          {
            "lang": "es",
            "value": "Una ruptura criptoanal\u00edtica en el modo de ofuscaci\u00f3n Proof-of-Work de Altcha versi\u00f3n 0.8.0 y posteriores permite a los visitantes remotos recuperar el nonce de Proof-of-Work en tiempo constante mediante deducci\u00f3n matem\u00e1tica. NOTA: esto es disputado por el Proveedor porque el objetivo del producto es \u0027desalentar el scraping automatizado / bots, no garantizar la resistencia a atacantes decididos.\u0027 La documentaci\u00f3n establece \u0027el objetivo no es proporcionar un algoritmo criptogr\u00e1fico seguro sino utilizar un mecanismo de prueba de trabajo que permita a cualquier dispositivo capaz descifrar los datos ocultos.\u0027"
          }
        ],
        "id": "CVE-2025-65849",
        "lastModified": "2026-10-18T15:10:00.097",
        "metrics": {
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                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 9.1,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.2,
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
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              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
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                "options": [
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                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2025-12-08T19:15:50.817",
        "references": [
          {
            "source": "cve@mitre.org",
            "url": "https://altcha.org/docs/v2/obfuscation/"
          },
          {
            "source": "cve@mitre.org",
            "url": "https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194"
          },
          {
            "source": "cve@mitre.org",
            "url": "https://github.com/eternal-flame-AD/altcha-deobfs"
          }
        ],
        "sourceIdentifier": "cve@mitre.org",
        "vulnStatus": "Deferred",
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            "type": "Secondary"
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        ]
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    },
    "redhat_vex": {
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      "initial_release_date": "2025-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
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      "title": "CVE-2025-65849",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-65849.json",
      "version": "3"
    },
    "vulnrichment": {
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              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
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              "vendor": "n/a",
              "versions": [
                {
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                  "version": "n/a"
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          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "A cryptanalytic break in Altcha Proof-of-Work obfuscation mode version 0.8.0 and later allows for remote visitors to recover the Proof-of-Work nonce in constant time via mathematical deduction. NOTE: this is disputed by the Supplier because the product\u0027s objective is \"to discourage automated scraping / bots, not guarantee resistance to determined attackers.\" The documentation states \u201cthe goal is not to provide a secure cryptographic algorithm but to use a proof-of-work mechanism that allows any capable device to decrypt the hidden data.\u201d"
            }
          ],
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          "references": [
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              "url": "https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194"
            },
            {
              "url": "https://altcha.org/docs/v2/obfuscation/"
            },
            {
              "url": "https://github.com/eternal-flame-AD/altcha-deobfs"
            }
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          "tags": [
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}

FKIE_CVE-2025-65849

Vulnerability from fkie_nvd - Published: 2025-12-08 19:15 - Updated: 2026-10-18 15:10

Severity

9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Summary

References

	URL	Tags
	cve@mitre.org	https://altcha.org/docs/v2/obfuscation/
	cve@mitre.org	https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194
	cve@mitre.org	https://github.com/eternal-flame-AD/altcha-deobfs

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "cveTags": [
    {
      "sourceIdentifier": "cve@mitre.org",
      "tags": [
        "disputed"
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A cryptanalytic break in Altcha Proof-of-Work obfuscation mode version 0.8.0 and later allows for remote visitors to recover the Proof-of-Work nonce in constant time via mathematical deduction. NOTE: this is disputed by the Supplier because the product\u0027s objective is \"to discourage automated scraping / bots, not guarantee resistance to determined attackers.\" The documentation states \u201cthe goal is not to provide a secure cryptographic algorithm but to use a proof-of-work mechanism that allows any capable device to decrypt the hidden data.\u201d"
    },
    {
      "lang": "es",
      "value": "Una ruptura criptoanal\u00edtica en el modo de ofuscaci\u00f3n Proof-of-Work de Altcha versi\u00f3n 0.8.0 y posteriores permite a los visitantes remotos recuperar el nonce de Proof-of-Work en tiempo constante mediante deducci\u00f3n matem\u00e1tica. NOTA: esto es disputado por el Proveedor porque el objetivo del producto es \u0027desalentar el scraping automatizado / bots, no garantizar la resistencia a atacantes decididos.\u0027 La documentaci\u00f3n establece \u0027el objetivo no es proporcionar un algoritmo criptogr\u00e1fico seguro sino utilizar un mecanismo de prueba de trabajo que permita a cualquier dispositivo capaz descifrar los datos ocultos.\u0027"
    }
  ],
  "id": "CVE-2025-65849",
  "lastModified": "2026-10-18T15:10:00.097",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
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          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2025-12-09T20:01:39.977561Z",
          "version": "2.0.3"
        }
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    ]
  },
  "published": "2025-12-08T19:15:50.817",
  "references": [
    {
      "source": "cve@mitre.org",
      "url": "https://altcha.org/docs/v2/obfuscation/"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://github.com/eternal-flame-AD/altcha-deobfs"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Deferred",
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    {
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        {
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        }
      ],
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      "type": "Secondary"
    }
  ]
}

GHSA-MPMC-QCHH-R9Q8

Vulnerability from github – Published: 2025-12-08 21:30 – Updated: 2025-12-12 19:39

Summary

Altcha Proof-of-Work obfuscation mode cryptanalytic break

Details

A cryptanalytic break in Altcha Proof-of-Work obfuscation mode version 0.8.0 and later allows for remote visitors to recover the Proof-of-Work nonce in constant time via mathematical deduction.

Severity

5.5 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "altcha"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.8.0"
            },
            {
              "last_affected": "2.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-65849"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-327"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-12-09T14:26:12Z",
    "nvd_published_at": "2025-12-08T19:15:50Z",
    "severity": "MODERATE"
  },
  "details": "A cryptanalytic break in Altcha Proof-of-Work obfuscation mode version 0.8.0 and later allows for remote visitors to recover the Proof-of-Work nonce in constant time via mathematical deduction.",
  "id": "GHSA-mpmc-qchh-r9q8",
  "modified": "2025-12-12T19:39:35Z",
  "published": "2025-12-08T21:30:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-65849"
    },
    {
      "type": "WEB",
      "url": "https://altcha.org/docs/v2/obfuscation"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/altcha-org/altcha"
    },
    {
      "type": "WEB",
      "url": "https://github.com/altcha-org/altcha/blob/154f874cbcdd4e639783463130d13988a2bd1bdc/src/helpers.ts#L170-L194"
    },
    {
      "type": "WEB",
      "url": "https://github.com/eternal-flame-AD/altcha-deobfs"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Altcha Proof-of-Work obfuscation mode cryptanalytic break"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

Publication & reservation Sightings KEV catalogs Other timestamps

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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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CVE-2025-65849 (GCVE-0-2025-65849)

FKIE_CVE-2025-65849

GHSA-MPMC-QCHH-R9Q8

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Vulnerability timeline

Related by attack behaviour