libgcrypt20 vulnerabilities

CVE-2026-41989

Libgcrypt before 1.12.2 sometimes allows a heap-based buffer overflow and denial of service via crafted ECDH ciphertext to gcry_pk_decrypt.

Libgcrypt: vulnerable to marvin attack

A timing-based side-channel flaw was found in libgcrypt's RSA implementation. This issue may allow a remote attacker to initiate a Bleichenbacher-style attack, which can lead to the decryption of RSA ciphertexts.

CVE-2021-40528

The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.

• Update to 1.6.5-2ubuntu0.6+esm1

CVE-2021-33560

Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately. This, for example, affects use of ElGamal in OpenPGP.

• Update to 1.6.5-2ubuntu0.6+esm1