CVE-2015-7499

What it actually does

Heap-based buffer overflow in the xmlGROW function within parser.c allows reading beyond allocated memory bounds, exposing adjacent heap contents containing sensitive process data.

Why it matters to the business

Attackers can extract fragments of process memory from systems parsing untrusted XML, increasing risk of credential or data leakage across widely deployed operating systems and applications.

How an attack unfolds

An attacker supplies a specially crafted XML document to a vulnerable application using libxml2; the parser's xmlGROW routine overflows the heap buffer, and the resulting memory contents are returned or leaked through the application's response or error handling.

How to fix it

Upgrade libxml2 to version 2.9.3 or later on all affected systems; rebuild or redeploy dependent applications against the patched library; verify no custom builds retain the vulnerable parser.c code.

How to confirm the fix worked

Confirm installed libxml2 version is 2.9.3 or newer using package manager queries or xml2-config --version; run regression tests with known boundary XML inputs to ensure no overflow occurs.

Typical attack path

1. Identify an application or service that processes attacker-controlled XML using a vulnerable libxml2 version
2. Craft malicious XML input designed to trigger excessive growth in the parser buffer
3. Submit the input via network request, file upload, or API call
4. Observe or extract leaked heap memory fragments containing sensitive process information

How to detect it

Review application logs and network captures for unusually large or malformed XML payloads; inspect process memory dumps or error logs for unexpected data leakage patterns; correlate with use of libxml2 versions prior to 2.9.3.

What your security team should do

• Prioritize patching libxml2 on internet-facing systems and those handling untrusted XML
• Inventory all applications linking against libxml2 and schedule upgrades
• Monitor EPSS score for any future increase indicating rising exploit likelihood