FKIE_CVE-2026-52778

Vulnerability from fkie_nvd - Published: 2026-06-08 19:16 - Updated: 2026-07-23 08:10
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
YesWiki is a wiki system written in PHP. Prior to version 4.6.6, an unsafe execution vulnerability exists in the Bazar form field calculator (CalcField.php) of YesWiki. The application attempts to sanitize user-defined mathematical formulas using a complex recursive regular expression before passing them to the PHP eval() function. This implementation is inherently flawed: it is vulnerable to Regular Expression Denial of Service (ReDoS / Stack Overflow) which can crash the server, and it creates a high-risk architecture where any logic bypass directly results in arbitrary PHP code execution. Version 4.6.6 patches the issue.
References
security-advisories@github.comhttps://github.com/YesWiki/yeswiki/commit/dd2bd8fb099de0d21504bda8a810693b3fcb8e52
security-advisories@github.comhttps://github.com/YesWiki/yeswiki/releases/tag/v4.6.6
security-advisories@github.comhttps://github.com/YesWiki/yeswiki/security/advisories/GHSA-px5m-h76g-p7p8
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/YesWiki/yeswiki/security/advisories/GHSA-px5m-h76g-p7p8
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "yeswiki",
          "vendor": "YesWiki",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 4.6.6"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "YesWiki is a wiki system written in PHP. Prior to version 4.6.6, an unsafe execution vulnerability exists in the Bazar form field calculator (CalcField.php) of YesWiki. The application attempts to sanitize user-defined mathematical formulas using a complex recursive regular expression before passing them to the PHP eval() function. This implementation is inherently flawed: it is vulnerable to Regular Expression Denial of Service (ReDoS / Stack Overflow) which can crash the server, and it creates a high-risk architecture where any logic bypass directly results in arbitrary PHP code execution. Version 4.6.6 patches the issue."
    },
    {
      "lang": "es",
      "value": "YesWiki es un sistema wiki escrito en PHP. Antes de la versi\u00f3n 4.6.6, existe una vulnerabilidad de ejecuci\u00f3n insegura en la calculadora de campos de formulario Bazar (CalcField.php) de YesWiki. La aplicaci\u00f3n intenta sanear f\u00f3rmulas matem\u00e1ticas definidas por el usuario utilizando una expresi\u00f3n regular recursiva compleja antes de pasarlas a la funci\u00f3n PHP eval(). Esta implementaci\u00f3n es inherentemente defectuosa: es vulnerable a la denegaci\u00f3n de servicio por expresi\u00f3n regular (ReDoS / desbordamiento de pila) lo que puede bloquear el servidor, y crea una arquitectura de alto riesgo donde cualquier omisi\u00f3n de l\u00f3gica resulta directamente en la ejecuci\u00f3n arbitraria de c\u00f3digo PHP. La versi\u00f3n 4.6.6 corrige el problema."
    }
  ],
  "id": "CVE-2026-52778",
  "lastModified": "2026-07-23T08:10:00.137",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "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:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-52778",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-09T15:54:35.483833Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-08T19:16:46.683",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/YesWiki/yeswiki/commit/dd2bd8fb099de0d21504bda8a810693b3fcb8e52"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/YesWiki/yeswiki/security/advisories/GHSA-px5m-h76g-p7p8"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/YesWiki/yeswiki/security/advisories/GHSA-px5m-h76g-p7p8"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-94"
        },
        {
          "lang": "en",
          "value": "CWE-1333"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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