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CVE-2007-1521

Status: ModifiedMedium (6.8)—Exploit
Severity6.8Medium · CVSS 2.0
Exploitation probability8.61 %higher than 95% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitAvailablePublished on Exploit-DB

Double free vulnerability in PHP before 4.4.7, and 5.x before 5.2.2, allows context-dependent attackers to execute arbitrary code by interrupting the session_regenerate_id function, as demonstrated by calling a userspace error handler or triggering a memory limit violation.

CVSS

Base score
6.8
Version
2.0
Vector
AV:N/AC:M/Au:N/C:P/I:P/A:P

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
8.61 %
Percentile among all scored CVEs
95
Score date
10/24/2026

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 42 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2007-1521",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 6.8,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:P",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 6.4,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8.6,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": true,
        "userInteractionRequired": false
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2007-03-20T20:19:00.000",
  "references": [
    {
      "url": "http://docs.info.apple.com/article.html?artnum=306172",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://lists.apple.com/archives/security-announce//2007/Jul/msg00004.html",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://secunia.com/advisories/24505",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "http://secunia.com/advisories/25025",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "http://secunia.com/advisories/25056",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://secunia.com/advisories/25057",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "http://secunia.com/advisories/25062",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "http://secunia.com/advisories/25445",
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    },
    {
      "url": "http://secunia.com/advisories/26235",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://security.gentoo.org/glsa/glsa-200705-19.xml",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://us2.php.net/releases/4_4_7.php",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://us2.php.net/releases/5_2_2.php",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.debian.org/security/2007/dsa-1282",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.debian.org/security/2007/dsa-1283",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.novell.com/linux/security/advisories/2007_32_php.html",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.php-security.org/MOPB/MOPB-22-2007.html",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.securityfocus.com/bid/22968",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.securityfocus.com/bid/25159",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.ubuntu.com/usn/usn-455-1",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.vupen.com/english/advisories/2007/0960",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://www.vupen.com/english/advisories/2007/2732",
      "source": "cve@mitre.org"
    },
    {
      "url": "http://docs.info.apple.com/article.html?artnum=306172",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://lists.apple.com/archives/security-announce//2007/Jul/msg00004.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://secunia.com/advisories/24505",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://secunia.com/advisories/25025",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://secunia.com/advisories/25056",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://secunia.com/advisories/25057",
      "tags": [
        "Vendor Advisory"
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
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      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://secunia.com/advisories/25445",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://secunia.com/advisories/26235",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://security.gentoo.org/glsa/glsa-200705-19.xml",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://us2.php.net/releases/4_4_7.php",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://us2.php.net/releases/5_2_2.php",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.debian.org/security/2007/dsa-1282",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.debian.org/security/2007/dsa-1283",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.novell.com/linux/security/advisories/2007_32_php.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.php-security.org/MOPB/MOPB-22-2007.html",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securityfocus.com/bid/22968",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securityfocus.com/bid/25159",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.ubuntu.com/usn/usn-455-1",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.vupen.com/english/advisories/2007/0960",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.vupen.com/english/advisories/2007/2732",
      "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": "Double free vulnerability in PHP before 4.4.7, and 5.x before 5.2.2, allows context-dependent attackers to execute arbitrary code by interrupting the session_regenerate_id function, as demonstrated by calling a userspace error handler or triggering a memory limit violation."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de doble liberación en PHP versiones anteriores a 4.4.7, y versiones 5.x anteriores a 5.2.2, permite a atacantes dependiendo del contexto ejecutar código arbitrario mediante la interrupción de la función session_regenerate_id, como es demostrado mediante la llamada de un manejador de errores de espacio de usuario o desencadenando una violación de límite de memoria."
    }
  ],
  "lastModified": "2026-06-16T22:37:45.100",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:php:php:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "FEE12690-B08D-4AB2-8092-013DE1A33C4C",
              "versionEndIncluding": "5.2.1"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "vendorComments": [
    {
      "comment": "The PHP interpreter does not offer a reliable "sandboxed" security\nlayer (as found in, say, a JVM) in which untrusted scripts can be run;\nany script run by the PHP interpreter must be trusted with the\nprivileges of the interpreter itself.  We therefore do not classify\nthis issue as security-sensitive since no trust boundary is crossed.\n",
      "lastModified": "2007-04-16T00:00:00",
      "organization": "Red Hat"
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}