CVE-2022-27405

What it actually does

Heap buffer overflow in FreeType font parsing routines caused by insufficient bounds validation when processing malformed TrueType or OpenType font data structures.

Why it matters to the business

Applications that render user-supplied or untrusted fonts may crash or allow arbitrary code execution, exposing desktop, server, and embedded systems to compromise through document viewers, browsers, and print services that depend on the library.

How an attack unfolds

An attacker supplies a specially crafted font file containing oversized or malformed tables; when the vulnerable FreeType instance loads and parses the file, the overflow occurs on the heap, enabling control-flow hijacking or memory corruption that can lead to code execution within the host process.

How to fix it

Upgrade FreeType to the commit e50798b72043c8b378caa46e0a854519f9028ae4 or later; rebuild and redeploy all dependent applications and libraries; where immediate patching is not feasible, isolate or sandbox font-processing components.

How to confirm the fix worked

Confirm the installed FreeType binary or source matches or exceeds commit e50798b72043c8b378caa46e0a854519f9028ae4; run regression test suites against known-malformed font samples; monitor build pipelines for the updated library version.

Typical attack path

1. Identify or craft a malicious font file that triggers the overflow condition in sfnt/ttload or related parsing code
2. Deliver the font via a document, web page, or application that uses FreeType to render text
3. Trigger font loading and parsing in the target process
4. Leverage the resulting heap corruption to execute attacker-controlled code or cause denial of service

How to detect it

Review application logs and crash reports for segmentation faults or heap corruption during font loading; inspect process memory dumps or audit trails for unexpected font file handling; correlate with file-creation or download events involving .ttf or .otf files.

What your security team should do

• Prioritize patching of internet-facing systems and any service that processes untrusted documents or fonts
• Inventory all products and containers that statically or dynamically link FreeType and schedule upgrades
• Apply least-privilege sandboxing around font-rendering code paths until patches are deployed
• Update vulnerability management dashboards with the fixed commit hash to track closure