CVE-2015-5821

Vulnerability

CVE-2015-5821 is a memory corruption vulnerability in WebKit, as used in Apple iOS versions prior to 9 and iTunes versions prior to 12.3 [1][3]. The bug can be triggered when a user visits a maliciously crafted website. The official description notes that this is a different vulnerability than other WebKit CVEs addressed in the same security updates. No further technical details about the specific code path or affected WebKit component are disclosed in the available references.

Exploitation

An attacker can exploit this vulnerability by hosting a specially crafted website and enticing a user to visit that site. No authentication or special network position is required beyond the ability to serve web content. User interaction is limited to the user navigating to the malicious website. The vulnerability is remotely exploitable through the WebKit rendering engine.

Impact

Successful exploitation could allow a remote attacker to execute arbitrary code on the affected device within the context of the WebKit process, or cause a denial of service through memory corruption and application crash. The full impact depends on the version of iOS or iTunes, but in iOS the attacker could potentially gain elevated privileges (code execution in a sandboxed WebKit process), while in iTunes it could lead to code execution or application termination.

Mitigation

Apple addressed this vulnerability by releasing iOS 9 on September 16, 2015, and iTunes 12.3 on September 16, 2015 [1][3][2]. Users should update to these or later versions. No workarounds or mitigations are described in the references. The vulnerability is not listed on the CISA Known Exploited Vulnerabilities (KEV) catalog as of the publication date.