PDFium in Google Chrome prior to 54.0.2840.59 for Windows, Mac, and Linux; 54.0.2840.85 for Android incorrectly handled object lifecycles in CFFL_FormFillter::KillFocusForAnnot, which allowed a remote attacker to potentially exploit heap corruption via crafted PDF files.
https://security.gentoo.org/glsa/201610-09
https://chromereleases.googleblog.com/2016/10/stable-channel-update-for-desktop.html