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CVE-2011-0420

Status: ModifiedMedium (5)—Exploit
Severity5Medium · CVSS 2.0
Exploitation probability14 %higher than 97% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitAvailablePublished on Exploit-DB

The grapheme_extract function in the Internationalization extension (Intl) for ICU for PHP 5.3.5 allows context-dependent attackers to cause a denial of service (crash) via an invalid size argument, which triggers a NULL pointer dereference.

CVSS

Base score
5
Version
2.0
Vector
AV:N/AC:L/Au:N/C:N/I:N/A:P

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
14 %
Percentile among all scored CVEs
97
Score date
10/21/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

Affected technologies (1)

PHP — PHP

CWEs

References

Show 24 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2011-0420",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ]
  },
  "affected": [
    {
      "source": "cret@cert.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2011-02-19T01:00:02.933",
  "references": [
    {
      "url": "http://lists.apple.com/archives/Security-announce/2011//Oct/msg00003.html",
      "source": "cret@cert.org"
    },
    {
      "url": "http://securityreason.com/achievement_securityalert/94",
      "tags": [
        "Exploit"
      ],
      "source": "cret@cert.org"
    },
    {
      "url": "http://securityreason.com/securityalert/8087",
      "source": "cret@cert.org"
    },
    {
      "url": "http://support.apple.com/kb/HT5002",
      "source": "cret@cert.org"
    },
    {
      "url": "http://svn.php.net/viewvc/php/php-src/trunk/ext/intl/grapheme/grapheme_string.c?r1=306449&r2=306448&pathrev=306449",
      "tags": [
        "Patch"
      ],
      "source": "cret@cert.org"
    },
    {
      "url": "http://www.debian.org/security/2011/dsa-2266",
      "source": "cret@cert.org"
    },
    {
      "url": "http://www.exploit-db.com/exploits/16182",
      "source": "cret@cert.org"
    },
    {
      "url": "http://www.kb.cert.org/vuls/id/210829",
      "tags": [
        "US Government Resource"
      ],
      "source": "cret@cert.org"
    },
    {
      "url": "http://www.securityfocus.com/archive/1/516504/100/0/threaded",
      "source": "cret@cert.org"
    },
    {
      "url": "http://www.securityfocus.com/archive/1/516518/100/0/threaded",
      "source": "cret@cert.org"
    },
    {
      "url": "http://www.securityfocus.com/bid/46429",
      "tags": [
        "Exploit"
      ],
      "source": "cret@cert.org"
    },
    {
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/65437",
      "source": "cret@cert.org"
    },
    {
      "url": "http://lists.apple.com/archives/Security-announce/2011//Oct/msg00003.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://securityreason.com/achievement_securityalert/94",
      "tags": [
        "Exploit"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://securityreason.com/securityalert/8087",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://support.apple.com/kb/HT5002",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://svn.php.net/viewvc/php/php-src/trunk/ext/intl/grapheme/grapheme_string.c?r1=306449&r2=306448&pathrev=306449",
      "tags": [
        "Patch"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.debian.org/security/2011/dsa-2266",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.exploit-db.com/exploits/16182",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.kb.cert.org/vuls/id/210829",
      "tags": [
        "US Government Resource"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securityfocus.com/archive/1/516504/100/0/threaded",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securityfocus.com/archive/1/516518/100/0/threaded",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securityfocus.com/bid/46429",
      "tags": [
        "Exploit"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/65437",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-Other"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The grapheme_extract function in the Internationalization extension (Intl) for ICU for PHP 5.3.5 allows context-dependent attackers to cause a denial of service (crash) via an invalid size argument, which triggers a NULL pointer dereference."
    },
    {
      "lang": "es",
      "value": "La función grapheme_extract en la extensión de Internacionalización (Intl) para ICU para PHP v5.3.5 permite provocar una denegación de servicio (con caída de la aplicación) a atacantes dependientes del contexto a través de un argumento de tamaño no válido, lo que provoca una desreferencia de puntero NULL."
    }
  ],
  "lastModified": "2026-06-16T23:27:19.550",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:php:php:5.3.5:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A9E6D530-91FC-42F4-A427-6601238E0187"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "evaluatorComment": "Per: http://cwe.mitre.org/data/definitions/476.html\r\n'CWE-476: NULL Pointer Dereference'",
  "sourceIdentifier": "cret@cert.org"
}