May 30, 2017
Left 4 Dead - Valve
An update has been released for Left 4 Dead.

- Fixed a potential remote code execution exploit.
Mar 24, 2016
Left 4 Dead - Valve
An update has been released for Left 4 Dead.

- Fixed exploits that could allow remote code execution.
- Remove forced shutdown when ctrl-alt-del is pressed.
- Protect against a reported crash caused by a map name parsing failure.
- Protect against a reported crash when returning to a lobby.
Feb 23, 2016
Left 4 Dead - Valve
An update has been released for Left 4 Dead.

- Updated binaries to improve crash reports.
Feb 18, 2016
Left 4 Dead - Valve
An update has been released for Left 4 Dead.

- Fixed an exploit that could allow remote code execution.
Feb 1, 2016
Left 4 Dead - Valve
An update has been released for Left 4 Dead

- Fixed two exploits that could allow remote code execution.
Oct 14, 2015
Left 4 Dead - Valve
An update has been released for Left 4 Dead.

- Fixed an exploit that could shut down dedicated servers.
- Fixed several buffer overflow exploits with networked files.
- Fixed a series of exploits caused by invalid or malformed textures.
May 20, 2014
Left 4 Dead - Valve
An update has been released for Left 4 Dead.

- Fixed the game failing to launch on some versions of Mac OS.
May 13, 2014
Left 4 Dead - Valve
An update has been released for Left 4 Dead.

- Enabled SteamCmd depot for dedicated server operators.
- Fixed an exploit that could allow clients to transfer blacklisted files to and from the server.
Dec 5, 2012
Left 4 Dead - Valve
- Fixed a potential crash in the client shadow manager
- Fixed the game and tools not launching on machines with 16+ CPUs.
- Enable controller navigation of menus to support Big Picture mode.
Left 4 Dead - Valve
Updates to Left 4 Dead have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

- Fixed a crash when attempting to play Single Player
- Fixed a possible buffer overflow in localized strings
- Fixed a networkID exploit that allowed players to avoid getting banned
- Fixed some images not rendering correctly on the dedicated server welcome screen
...