CVE-2026-21640 (GCVE-0-2026-21640)

Vulnerability from cvelistv5 – Published: 2026-01-20 20:48 – Updated: 2026-01-21 18:52
VLAI?
Summary
HackerOne community member Faraz Ahmed (PakCyberbot) has reported a format string injection in the Revive Adserver settings. When specific character combinations are used in a setting, the admin user console could be disabled due to a fatal PHP error.
Severity ?
2.7 (Low)
CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
CWE
  • CWE-134 - Use of Externally-Controlled Format String
Assigner
References
Impacted products
Vendor Product Version
Revive Revive Adserver Affected: 6 , ≤ 6.0.4 (semver)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-21640",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-21T18:32:40.483218Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-134",
                "description": "CWE-134 Use of Externally-Controlled Format String",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-21T18:52:43.635Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Revive Adserver",
          "vendor": "Revive",
          "versions": [
            {
              "lessThanOrEqual": "6.0.4",
              "status": "affected",
              "version": "6",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "HackerOne community member Faraz Ahmed (PakCyberbot) has reported a format string injection in the Revive Adserver settings. When specific character combinations are used in a setting, the admin user console could be disabled due to a fatal PHP error."
        }
      ],
      "metrics": [
        {
          "cvssV3_0": {
            "baseScore": 2.7,
            "baseSeverity": "LOW",
            "vectorString": "CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L",
            "version": "3.0"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-20T20:48:47.940Z",
        "orgId": "36234546-b8fa-4601-9d6f-f4e334aa8ea1",
        "shortName": "hackerone"
      },
      "references": [
        {
          "url": "https://hackerone.com/reports/3445332"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "36234546-b8fa-4601-9d6f-f4e334aa8ea1",
    "assignerShortName": "hackerone",
    "cveId": "CVE-2026-21640",
    "datePublished": "2026-01-20T20:48:47.940Z",
    "dateReserved": "2026-01-01T15:00:02.339Z",
    "dateUpdated": "2026-01-21T18:52:43.635Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-21640\",\"sourceIdentifier\":\"support@hackerone.com\",\"published\":\"2026-01-20T21:16:06.063\",\"lastModified\":\"2026-01-21T19:16:05.663\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"HackerOne community member Faraz Ahmed (PakCyberbot) has reported a format string injection in the Revive Adserver settings. When specific character combinations are used in a setting, the admin user console could be disabled due to a fatal PHP error.\"}],\"metrics\":{\"cvssMetricV30\":[{\"source\":\"support@hackerone.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.0\",\"vectorString\":\"CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L\",\"baseScore\":2.7,\"baseSeverity\":\"LOW\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"HIGH\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":1.2,\"impactScore\":1.4}]},\"weaknesses\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-134\"}]}],\"references\":[{\"url\":\"https://hackerone.com/reports/3445332\",\"source\":\"support@hackerone.com\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-21640\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-01-21T18:32:40.483218Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-134\", \"description\": \"CWE-134 Use of Externally-Controlled Format String\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-01-21T18:35:26.346Z\"}}], \"cna\": {\"metrics\": [{\"cvssV3_0\": {\"version\": \"3.0\", \"baseScore\": 2.7, \"baseSeverity\": \"LOW\", \"vectorString\": \"CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L\"}}], \"affected\": [{\"vendor\": \"Revive\", \"product\": \"Revive Adserver\", \"versions\": [{\"status\": \"affected\", \"version\": \"6\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.0.4\"}], \"defaultStatus\": \"unaffected\"}], \"references\": [{\"url\": \"https://hackerone.com/reports/3445332\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"HackerOne community member Faraz Ahmed (PakCyberbot) has reported a format string injection in the Revive Adserver settings. When specific character combinations are used in a setting, the admin user console could be disabled due to a fatal PHP error.\"}], \"providerMetadata\": {\"orgId\": \"36234546-b8fa-4601-9d6f-f4e334aa8ea1\", \"shortName\": \"hackerone\", \"dateUpdated\": \"2026-01-20T20:48:47.940Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-21640\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-01-21T18:52:43.635Z\", \"dateReserved\": \"2026-01-01T15:00:02.339Z\", \"assignerOrgId\": \"36234546-b8fa-4601-9d6f-f4e334aa8ea1\", \"datePublished\": \"2026-01-20T20:48:47.940Z\", \"assignerShortName\": \"hackerone\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

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.