Vulnerability-Lookup

GHSA-WMGQ-9Q82-422R

Vulnerability from github – Published: 2026-06-03 18:33 – Updated: 2026-06-03 21:30

Details

Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 uses a static authentication nonce that does not change between requests from the same source IP. Combined with the predictable XOR-based password encoding (securityEncode function), this allows an attacker to reverse captured authentication tokens to recover the plaintext password.

Severity

7.3 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-36609"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-327"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-03T18:16:22Z",
    "severity": "HIGH"
  },
  "details": "Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 uses a static authentication nonce that does not change between requests from the same source IP. Combined with the predictable XOR-based password encoding (securityEncode function), this allows an attacker to reverse captured authentication tokens to recover the plaintext password.",
  "id": "GHSA-wmgq-9q82-422r",
  "modified": "2026-06-03T21:30:29Z",
  "published": "2026-06-03T18:33:11Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-36609"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Tymbark7372/MERCUSYS-AC12G/blob/master/advisories/CVE-2026-36609.md"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-36609 (GCVE-0-2026-36609)

Vulnerability from cvelistv5 – Published: 2026-06-03 00:00 – Updated: 2026-06-03 19:38

Summary

Severity

7.3 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

n/a
CWE-341 - Predictable from Observable State
CWE-327 - Use of a Broken or Risky Cryptographic Algorithm

Assigner

mitre

References

1 reference

URL	Tags
https://github.com/Tymbark7372/MERCUSYS-AC12G/blo…

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "LOW",
              "baseScore": 7.3,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "LOW",
              "integrityImpact": "LOW",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-36609",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-03T19:37:08.505131Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-341",
                "description": "CWE-341 Predictable from Observable State",
                "lang": "en",
                "type": "CWE"
              }
            ]
          },
          {
            "descriptions": [
              {
                "cweId": "CWE-327",
                "description": "CWE-327 Use of a Broken or Risky Cryptographic Algorithm",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-03T19:38:09.934Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mercusys AC12G (EU) V1 router with firmware AC12G(EU)_V1_200909 uses a static authentication nonce that does not change between requests from the same source IP. Combined with the predictable XOR-based password encoding (securityEncode function), this allows an attacker to reverse captured authentication tokens to recover the plaintext password."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-03T16:09:04.378Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://github.com/Tymbark7372/MERCUSYS-AC12G/blob/master/advisories/CVE-2026-36609.md"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-36609",
    "datePublished": "2026-06-03T00:00:00.000Z",
    "dateReserved": "2026-04-06T00:00:00.000Z",
    "dateUpdated": "2026-06-03T19:38:09.934Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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-WMGQ-9Q82-422R

CVE-2026-36609 (GCVE-0-2026-36609)

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Sightings

Nomenclature