I think this affects gdk-pixbuf 2.31 and above. Not sure which version is on Mageia 5.
Steps to Reproduce:
Mageia 5 has gdk-pixbuf2.0-2.31.2-2.mga5.src.rpm so probably affected.
Fixed in Mageia 5 SVN.
Apparently this is the CVE-2015-4491 issue that was fixed in Firefox 38.2:
Updated gdk-pixbuf packages fix security vulnerability:
Security researcher Gustavo Grieco reported a heap overflow in gdk-pixbuf.
This issue is triggered by the scaling of a malformed bitmap format image and
results in a potentially exploitable crash (CVE-2015-4491).
Updated packages in core/updates_testing:
Testing Mageia 5 x64, using:
firefox-38.2.0-1.mga5 (just updated)
Looked at flickr.com, just photographs. No problems.
An update for this issue has been pushed to Mageia Updates repository.