#VU43931 Input validation error in WordPress - CVE-2011-4957

Vulnerability identifier: #VU43931

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2011-4957

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
WordPress
Web applications / CMS

Vendor: WordPress.ORG

Description

The vulnerability allows a remote non-authenticated attacker to perform service disruption.

The make_clickable function in wp-includes/formatting.php in WordPress before 3.1.1 does not properly check URLs before passing them to the PCRE library, which allows remote attackers to cause a denial of service (crash) via a comment with a crafted URL that triggers many recursive calls.

Mitigation
Install update from vendor's website.

Vulnerable software versions

WordPress: 0.71, 1.0 - 1.0.2, 1.1.1, 1.2 - 1.2.5, 1.3, 1.3.2, 1.3.3, 1.5 - 1.5.2, 2.0 - 2.0.11, 2.1 - 2.1.3, 2.2 - 2.2.3, 2.3 - 2.3.3, 2.5 - 2.5.1, 2.6 - 2.6.5, 2.7 - 2.7.1, 2.8 - 2.8.6, 2.9 - 2.9.2, 3.0 - 3.0.6

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External links
https://core.trac.wordpress.org/ticket/16892
https://secunia.com/advisories/44038
https://secunia.com/advisories/49138
https://wordpress.org/news/2011/04/wordpress-3-1-1/
https://www.debian.org/security/2012/dsa-2470
https://www.openwall.com/lists/oss-security/2012/04/19/17
https://www.openwall.com/lists/oss-security/2012/04/19/6

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.