Libgcrypt before 1.5.4, as used in GnuPG and other products, does not properly perform ciphertext normalization and ciphertext randomization, which makes it easier for physically proximate attackers to conduct key-extraction attacks by leveraging the ability to collect voltage data from exposed metal, a different vector than CVE-2013-4576.

GnuPG 1.x before 1.4.16 generates RSA keys using sequences of introductions with certain patterns that introduce a side channel, which allows physically proximate attackers to extract RSA keys via a chosen-ciphertext attack and acoustic cryptanalysis during decryption. NOTE: applications are not typically expected to protect themselves from acoustic side-channel attacks, since this is arguably the responsibility of the physical device. Accordingly, issues of this type would not normally receive a CVE identifier. However, for this issue, the developer has specified a security policy in which GnuPG should offer side-channel resistance, and developer-specified security-policy violations are within the scope of CVE.