CVE-2009-4418

CVE-2009-4418 is a medium-severity vulnerability in Php with a CVSS 2.0 base score of 5.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-189.

Key facts

• Severity: Medium (CVSS 2.0 base score 5.0)
• EPSS exploit prediction: 1% (58th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-189
• Affected product: Php
• Published: 2009-12-24
• Last modified: 2026-06-16

Description

The unserialize function in PHP 5.3.0 and earlier allows context-dependent attackers to cause a denial of service (resource consumption) via a deeply nested serialized variable, as demonstrated by a string beginning with a:1: followed by many {a:1: sequences.

Frequently asked questions

What is CVE-2009-4418?

The unserialize function in PHP 5.3.0 and earlier allows context-dependent attackers to cause a denial of service (resource consumption) via a deeply nested serialized variable, as demonstrated by a string beginning with a:1: followed by many {a:1: sequences.

How severe is CVE-2009-4418?

CVE-2009-4418 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2009-4418 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-4418?

CVE-2009-4418 primarily affects Php. In total, 38 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-4418?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2009-4418 published?

CVE-2009-4418 was published on 2009-12-24 and last updated on 2026-06-16.

References

• http://www.suspekt.org/2009/11/28/shocking-news-in-php-exploitation/
• http://www.suspekt.org/downloads/POC2009-ShockingNewsInPHPExploitation.pdf

Affected products (38)

• cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0:rc1:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0:rc2:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0:rc3:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.0:beta1:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.0:beta2:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.0:beta3:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.0:beta4:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.0:rc1:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.0:rc2:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.0:rc3:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.1.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.1.1:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.1.2:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.1.3:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.1.4:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.1.5:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.1.6:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.1:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.2:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.3:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.4:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.4:*:windows:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.5:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.6:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.7:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.8:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.9:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.10:*:*:*:*:*:*:*
• cpe:2.3:a:php:php:5.2.11:*:*:*:*:*:*:*

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• CVE-2015-3864 — Critical (CVSS 10.0): Integer underflow in the MPEG4Extractor::parseChunk function in MPEG4Extractor.cpp in libstagefright in mediaserver in…
• CVE-2015-3836 — Critical (CVSS 10.0): The Parse_wave function in arm-wt-22k/lib_src/eas_mdls.c in the Sonivox DLS-to-EAS converter in Android before 5.1.1…
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Browse all CWE-189 (Numeric Errors) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

• 187.141.71.166 (ipv4-addr)
• 82.199.197.245 (ipv4-addr)
• 58.221.244.34 (ipv4-addr)
• 222.99.52.202 (ipv4-addr)
• 201.184.50.251 (ipv4-addr)
• 121.164.135.251 (ipv4-addr)
• 90.160.135.217 (ipv4-addr)
• 76.133.97.153 (ipv4-addr)