CVE-2015-8472

What it actually does

Buffer overflow in png_set_PLTE triggered by a small bit-depth value in an IHDR chunk of a PNG image, allowing memory corruption that can crash the application or lead to other unspecified impacts.

Why it matters to the business

Applications handling PNG images on affected systems can be crashed or potentially compromised, disrupting services that rely on image processing and increasing risk of further attacks in environments with high image-handling volume.

How an attack unfolds

An attacker creates a malicious PNG containing an IHDR chunk with a crafted small bit-depth value that bypasses the incomplete prior fix, then delivers the image to a target application using a vulnerable libpng version; when parsed, png_set_PLTE overflows the buffer leading to denial of service or potential code execution.

How to fix it

Upgrade libpng to 1.0.65 or later, 1.2.55 or later, 1.4.18 or later, 1.5.25 or later, or 1.6.20 or later depending on the branch in use; rebuild and redeploy any dependent applications after the library update.

How to confirm the fix worked

Verify installed libpng versions against the fixed releases listed in the advisory, run regression tests with known-malformed PNG samples that target IHDR bit-depth handling, and confirm absence of crashes under controlled parsing.

Typical attack path

1. Craft a PNG image with a malicious IHDR chunk specifying an invalid small bit-depth
2. Deliver the image via network, file upload, or email to an application using vulnerable libpng
3. Trigger PNG parsing which calls png_set_PLTE
4. Exploit the resulting buffer overflow to crash the process or attempt further memory corruption

How to detect it

Search application and system logs for crashes or segmentation faults occurring during PNG image parsing, inspect inbound PNG files for anomalous IHDR chunks with unusually small bit-depth values, and review any exploit artifacts related to the earlier incomplete fix for the referenced prior issue.

What your security team should do

• Prioritize patching libpng across all systems given the public disclosure and memory corruption nature
• Inventory all software and operating systems that bundle or depend on libpng including Apple macOS packages
• Implement network or application-layer filtering to block suspicious PNG uploads until patches are applied
• Monitor for application crashes correlated with PNG processing as an interim detection measure