CVE-2024-55549

What it actually does

Use-after-free vulnerability in xsltGetInheritedNsList triggered when excluding result prefixes during XSLT processing in libxslt before 1.1.43, leading to memory corruption.

Why it matters to the business

Applications relying on XML transformations may crash or be susceptible to remote code execution, potentially disrupting services that parse untrusted XSLT stylesheets; low exploitation likelihood based on EPSS and absence from KEV reduces immediate operational urgency.

How an attack unfolds

An attacker supplies a crafted XSLT stylesheet that exercises the result prefix exclusion path in xsltGetInheritedNsList, causing the use-after-free condition that can be leveraged for memory corruption and arbitrary code execution.

How to fix it

Upgrade libxslt to version 1.1.43 or later; apply the fix present in commit 71be7a32637760d769b193d95e0c745ecb86b679 across all affected products.

How to confirm the fix worked

Verify installed libxslt version is 1.1.43 or newer; re-run regression tests covering namespace inheritance and result prefix exclusion scenarios.

Typical attack path

1. Identify application entry points that process untrusted XSLT or XML documents via libxslt
2. Craft malicious stylesheet exploiting result prefix exclusion logic
3. Trigger xsltGetInheritedNsList to induce use-after-free
4. Corrupt memory state to achieve code execution or denial of service

How to detect it

Monitor application logs for segmentation faults or crashes during XSLT processing; inspect memory dumps or sanitizer reports for use-after-free patterns in libxslt namespace handling functions.

What your security team should do

• Prioritize upgrade of libxslt to 1.1.43 or the referenced commit in all dependencies
• Inventory applications and libraries using libxslt for XSLT processing
• Implement input validation or sandboxing around XSLT transformations until patched