The GNU Privacy Guard (GnuPG or GPG) is a tool for encrypting data and creating digital signatures, compliant with the proposed OpenPGP Internet standard and the S/MIME standard.
It was found that GnuPG was vulnerable to the Yarom/Falkner flush+reload cache side-channel attack on the RSA secret exponent. An attacker able to execute a process on the logical CPU that shared the L3 cache with the GnuPG process (such as a different local user or a user of a KVM guest running on the same host with the kernel same-page merging functionality enabled) could possibly use this flaw to obtain portions of the RSA secret key. (CVE-2013-4242)
A denial of service flaw was found in the way GnuPG parsed certain compressed OpenPGP packets. An attacker could use this flaw to send specially crafted input data to GnuPG, making GnuPG enter an infinite loop when parsing data. (CVE-2013-4402)
It was found that importing a corrupted public key into a GnuPG keyring database corrupted that keyring. An attacker could use this flaw to trick a local user into importing a specially crafted public key into their keyring database, causing the keyring to be corrupted and preventing its further use. (CVE-2012-6085)
It was found that GnuPG did not properly interpret the key flags in a PGP key packet. GPG could accept a key for uses not indicated by its holder. (CVE-2013-4351)
Red Hat would like to thank Werner Koch for reporting the CVE-2013-4402 issue. Upstream acknowledges Taylor R Campbell as the original reporter.
All gnupg users are advised to upgrade to this updated package, which contains backported patches to correct these issues.