Anti-Hack:
-Fix for exploit to start an online MP match with a custom game mode

Matchmaking:
-Prep work for adding Telemetry for matchmaking for future improvements.

PC Patch 1.14 (goes live June 21)

Matchmaking:
-Fix for missing .iwd files error causing non-dlc players to be booted from games (iw_25.iwd, iw_26.iwd)
-Fix for non-dlc owners being kicked from game when host migrates to DLC owner
-Change to match making where region searched is determined by party host

Game Balance:
-Dragunov (Weapon)
-Reduced kick to bring it more in line with RSASS
-Dead man's hand (Deathstreak)
-Reduced explosive radius apx. 25%
-Blast Shield (Perk)
-Increase damage reduction for Blast Shield in hardcore modes
-Akimbo (Attachment)
-All akimbo machine pistols now fire slower than their 1-handed counterparts
-LMGs (Weapon)
-Increased min damage for all LMGs

Game Modes:
-Kill Confirmed
-Update the player score before updating the team score
-Infected
-Removed fall damage
-Domination
-Fix for not all Domination defenses counting towards your "Defends" stat

Killstreaks:
-Reaper
-Fixed issue where a user wouldn't be able to call in his second Reaper

Perks:
-Blind Eye
-Fixed bug where the Blind Eye kill streak is taken from the player on round transition if earned from getting 8 kills
-Fixed bug where the Blind Eye kill streak is taken from the player if earned within 5 seconds of spawning
-Recon
-Fixed issue with flash grenades not correctly working with the Recon perk

Hot Fixes for PS3 and 360:
Maps:
-Liberation
-Added death trigger for rock glitch
-Black Box
-Patched up wall glitch
-Oasis
-Prevent players from getting on rooftops
-Foundation
-Patched up map hole in pipe

Game Balance:
-Javelin (Weapon)
-Reduce Javelin explosion radius by 20%
-UPDATED: Sit Rep Pro fix
-You can now see portable radars without being in their range

Player Stats:
-Fix for player accuracy being miscalculatedMisc Bug Fixes:
-Fix for minute long kill cam duration with Reaper

source ; http://community.callofduty.com/community/mw3/blog/2012/06/21/call-of-duty-modern-warfare-3-ps3-and-pc-title-update