CVE-2009-4018

CVE-2009-4018 is a high-severity vulnerability in Php with a CVSS 2.0 base score of 7.5. Its EPSS exploit-prediction score of 11% places it in the 95th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-264.

Key facts

• Severity: High (CVSS 2.0 base score 7.5)
• EPSS exploit prediction: 11% (95th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-264
• Affected product: Php
• Published: 2009-11-29
• Last modified: 2026-06-16

Description

The proc_open function in ext/standard/proc_open.c in PHP before 5.2.11 and 5.3.x before 5.3.1 does not enforce the (1) safe_mode_allowed_env_vars and (2) safe_mode_protected_env_vars directives, which allows context-dependent attackers to execute programs with an arbitrary environment via the env parameter, as demonstrated by a crafted value of the LD_LIBRARY_PATH environment variable.

Frequently asked questions

What is CVE-2009-4018?

The proc_open function in ext/standard/proc_open.c in PHP before 5.2.11 and 5.3.x before 5.3.1 does not enforce the (1) safe_mode_allowed_env_vars and (2) safe_mode_protected_env_vars directives, which allows context-dependent attackers to execute programs with an arbitrary environment via the env parameter, as demonstrated by a crafted value of the LD_LIBRARY_PATH environment variable.

How severe is CVE-2009-4018?

CVE-2009-4018 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-2009-4018 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-4018?

CVE-2009-4018 primarily affects Php. In total, 110 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-4018?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2009-4018 published?

CVE-2009-4018 was published on 2009-11-29 and last updated on 2026-06-16.

References

• http://bugs.php.net/bug.php?id=49026
• http://marc.info/?l=bugtraq&m=127680701405735&w=2
• http://marc.info/?l=oss-security&m=125886770008678&w=2
• http://marc.info/?l=oss-security&m=125897935330618&w=2
• http://secunia.com/advisories/40262
• http://secunia.com/advisories/41480
• http://secunia.com/advisories/41490
• http://svn.php.net/viewvc/?view=revision&revision=286360
• http://svn.php.net/viewvc/php/php-src/branches/PHP_5_2/ext/standard/proc_open.c?r1=286360&r2=286359&pathrev=286360
• http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3/ext/standard/proc_open.c?r1=286360&r2=286359&pathrev=286360
• http://www.itrc.hp.com/service/cki/docDisplay.do?docId=emr_na-c02512995
• http://www.mandriva.com/security/advisories?name=MDVSA-2009:303
• http://www.openwall.com/lists/oss-security/2009/11/23/15
• http://www.php.net/ChangeLog-5.php
• http://www.securityfocus.com/bid/37138
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7256

Affected products (110)

• cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:1.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:2.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:2.0b10:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.6:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.7:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.8:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.9:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.10:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.11:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.12:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.13:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.14:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.15:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.16:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.17:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:3.0.18:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:4:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0:beta_4_patch1:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0:beta1:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0:beta2:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0:beta3:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0:beta4:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0:rc1:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0:rc2:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0.1:patch1:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0.1:patch2:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0.3:patch1:*:*:*:*:*:*
• cpe:2.3:a:php:php:4.0.4:*:*:*:*:*:*:*

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All CVEs affecting Php →

Other CWE-264 (Permissions, Privileges, and Access Controls) vulnerabilities

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• CVE-2016-7457 — Critical (CVSS 10.0): VMware vRealize Operations (aka vROps) 6.x before 6.4.0 allows remote authenticated users to gain privileges, or halt…
• CVE-2015-7425 — Critical (CVSS 10.0): The Data Protection component in the VMware vSphere GUI in IBM Tivoli Storage Manager for Virtual Environments: Data…
• CVE-2015-8267 — Critical (CVSS 10.0): The PasswordReset.Controllers.ResetController.ChangePasswordIndex method in PasswordReset.dll in Dovestones AD Self…
• CVE-2015-7919 — Critical (CVSS 10.0): SearchBlox 8.3 before 8.3.1 allows remote attackers to write to the config file, and consequently cause a denial of…
• CVE-2015-7071 — Critical (CVSS 10.0): The File Bookmark component in Apple OS X before 10.11.2 allows attackers to bypass a sandbox protection mechanism for…

Browse all CWE-264 (Permissions, Privileges, and Access Controls) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

• 82.199.197.245 (ipv4-addr)
• 58.221.244.34 (ipv4-addr)
• 222.99.52.202 (ipv4-addr)
• 90.160.135.217 (ipv4-addr)
• 76.133.97.153 (ipv4-addr)
• 223.82.97.51 (ipv4-addr)
• 183.6.115.88 (ipv4-addr)
• 62.36.19.42 (ipv4-addr)