CVE-2009-4142

CVE-2009-4142 is a medium-severity vulnerability in Php with a CVSS 2.0 base score of 4.3. 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-79.

Key facts

• Severity: Medium (CVSS 2.0 base score 4.3)
• EPSS exploit prediction: 6% (93rd percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-79
• Affected product: Php
• Published: 2009-12-21
• Last modified: 2026-06-16

Description

The htmlspecialchars function in PHP before 5.2.12 does not properly handle (1) overlong UTF-8 sequences, (2) invalid Shift_JIS sequences, and (3) invalid EUC-JP sequences, which allows remote attackers to conduct cross-site scripting (XSS) attacks by placing a crafted byte sequence before a special character.

Frequently asked questions

What is CVE-2009-4142?

The htmlspecialchars function in PHP before 5.2.12 does not properly handle (1) overlong UTF-8 sequences, (2) invalid Shift_JIS sequences, and (3) invalid EUC-JP sequences, which allows remote attackers to conduct cross-site scripting (XSS) attacks by placing a crafted byte sequence before a special character.

How severe is CVE-2009-4142?

CVE-2009-4142 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2009-4142 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-4142?

CVE-2009-4142 primarily affects Php. In total, 111 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-4142?

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

When was CVE-2009-4142 published?

CVE-2009-4142 was published on 2009-12-21 and last updated on 2026-06-16.

References

• http://bugs.php.net/bug.php?id=49785
• http://lists.apple.com/archives/security-announce/2010//Mar/msg00001.html
• http://marc.info/?l=bugtraq&m=127680701405735&w=2
• http://secunia.com/advisories/37821
• http://secunia.com/advisories/38648
• http://secunia.com/advisories/40262
• http://securitytracker.com/id?1023372
• http://support.apple.com/kb/HT4077
• http://www.debian.org/security/2010/dsa-2001
• http://www.php.net/ChangeLog-5.php
• http://www.php.net/releases/5_2_12.php
• http://www.securityfocus.com/bid/37389
• http://www.vupen.com/english/advisories/2009/3593
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10005
• https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7085

Affected products (111)

• 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:*:*:*:*:*:*:*

More vulnerabilities in Php

• CVE-2015-0235 — Critical (CVSS 10.0): Heap-based buffer overflow in the __nss_hostname_digits_dots function in glibc 2.2, and other 2.x versions before 2.18,…
• CVE-2012-2688 — Critical (CVSS 10.0): Unspecified vulnerability in the _php_stream_scandir function in the stream implementation in PHP before 5.3.15 and…
• CVE-2012-2376 — Critical (CVSS 10.0): Buffer overflow in the com_print_typeinfo function in PHP 5.4.3 and earlier on Windows allows remote attackers to…
• CVE-2011-3268 — Critical (CVSS 10.0): Buffer overflow in the crypt function in PHP before 5.3.7 allows context-dependent attackers to have an unspecified…
• CVE-2009-4143 — Critical (CVSS 10.0): PHP before 5.2.12 does not properly handle session data, which has unspecified impact and attack vectors related to (1)…
• CVE-2008-5557 — Critical (CVSS 10.0): Heap-based buffer overflow in ext/mbstring/libmbfl/filters/mbfilter_htmlent.c in the mbstring extension in PHP 4.3.0…

All CVEs affecting Php →

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

• CVE-2025-49410 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Imran Emu TC…
• CVE-2024-47875 — Critical (CVSS 10.0): DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to…
• CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
• CVE-2023-45144 — Critical (CVSS 10.0): com.xwiki.identity-oauth:identity-oauth-ui is a package to aid in building identity and service providers based on…
• CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
• CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

Browse all CWE-79 (Cross-site Scripting (XSS)) 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)
• 121.164.135.251 (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)