CVE-2010-3870

Severity: medium (CVSS 6.8 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 11.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2010-11-12 · updated 2026-06-16
Weakness: CWE-20

Description

The utf8_decode function in PHP before 5.3.4 does not properly handle non-shortest form UTF-8 encoding and ill-formed subsequences in UTF-8 data, which makes it easier for remote attackers to bypass cross-site scripting (XSS) and SQL injection protection mechanisms via a crafted string.

Affected products

Canonical Ubuntu Linux: 6.06, 8.04, 9.10, 10.04, 10.10
PHP: before 5.2.14; from 5.3.0 before 5.3.4 — fixed in 5.2.14, 5.3.4

How to fix

Upgrade to a fixed version: PHP 5.2.14, 5.3.4. Check the vendor advisory for mitigations.

References

http://bugs.php.net/bug.php?id=48230
http://bugs.php.net/bug.php?id=49687
http://lists.apple.com/archives/security-announce/2011/Mar/msg00006.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-January/052836.html
http://lists.fedoraproject.org/pipermail/package-announce/2011-January/052845.html
http://lists.opensuse.org/opensuse-security-announce/2010-12/msg00000.html
http://marc.info/?l=bugtraq&m=133469208622507&w=2
http://secunia.com/advisories/42410
http://secunia.com/advisories/42812
http://sirdarckcat.blogspot.com/2009/10/couple-of-unicode-issues-on-php-and.html
http://support.apple.com/kb/HT4581
http://svn.php.net/viewvc?view=revision&revision=304959

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