USN-1923-1: GnuPG, Libgcrypt vulnerability

Ubuntu Security Notice USN-1923-1

31st July, 2013

gnupg, libgcrypt11 vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 13.04
  • Ubuntu 12.10
  • Ubuntu 12.04 LTS
  • Ubuntu 10.04 LTS


GnuPG and Libgcrypt could be made to expose sensitive information.

Software description

  • gnupg - GNU privacy guard - a free PGP replacement
  • libgcrypt11 - LGPL Crypto library - runtime library


Yuval Yarom and Katrina Falkner discovered a timing-based information leak,
known as Flush+Reload, that could be used to trace execution in programs.
GnuPG and Libgcrypt followed different execution paths based on key-related
data, which could be used to expose the contents of private keys.

Update instructions

The problem can be corrected by updating your system to the following package version:

Ubuntu 13.04:
libgcrypt11 1.5.0-3ubuntu2.2
gnupg 1.4.12-7ubuntu1.1
Ubuntu 12.10:
libgcrypt11 1.5.0-3ubuntu1.1
gnupg 1.4.11-3ubuntu4.2
Ubuntu 12.04 LTS:
libgcrypt11 1.5.0-3ubuntu0.2
gnupg 1.4.11-3ubuntu2.3
Ubuntu 10.04 LTS:
libgcrypt11 1.4.4-5ubuntu2.2
gnupg 1.4.10-2ubuntu1.3

To update your system, please follow these instructions:

In general, a standard system update will make all the necessary changes.