CVE-2018-0495
MediumCVSS 4.7Exploitation Probability (EPSS)
Elevated risk58th percentile - higher than 58% of all known CVEs
Summary
Libgcrypt before 1.7.10 and 1.8.x before 1.8.3 is vulnerable to a memory-cache side-channel attack on ECDSA signatures, known as Return Of the Hidden Number Problem (ROHNP). The attack can be mitigated by using blinding during the signing process in the _gcry_ecc_ecdsa_sign function. To discover an ECDSA key, the attacker needs access to either the local machine or a different virtual machine on the same physical host.
Risk Assessment
The risk is the potential disclosure of ECDSA keys, which could compromise the confidentiality of digital signatures and authentication. The attack requires local access or a shared environment, increasing the threat in cloud environments.
Recommendation
Upgrade Libgcrypt to version 1.7.10 or 1.8.3 or later to eliminate the vulnerability. In the meantime, implement blinding during ECDSA signing as a mitigation measure.
Other vulnerabilities in Libgcrypt
See all- CVE-2017-0379High
Libgcrypt before version 1.8.1 does not properly consider Curve25519 side-channel attacks, making it easier for attackers to discover a secret key.
- CVE-2026-41990Medium
Libgcrypt before 1.12.2 mishandles Dilithium signing. Writes to a static array lack a bounds check but do not use attacker-controlled data.
- CVE-2026-41989Medium
A vulnerability in Libgcrypt before version 1.12.2 allows a heap-based buffer overflow and denial of service via crafted ECDH ciphertext passed to gcry_pk_decrypt.
- CVE-2024-2236Medium
A timing-based side-channel flaw was found in libgcrypt's RSA implementation. It may allow a remote attacker to perform a Bleichenbacher-style attack, leading to decryption of RSA ciphertexts.
- CVE-2021-33560High
Vulnerability in Libgcrypt before versions 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption due to missing exponent blinding, enabling a side-channel attack on mpi_powm. Additionally, the window size is not chosen appropriately, increasing information leakage risk.
- CVE-2019-12904Medium
In Libgcrypt 1.8.4, the C implementation of AES is vulnerable to a flush-and-reload side-channel attack because physical addresses are available to other processes. (The C implementation is used on platforms where an assembly-language implementation is unavailable.) NOTE: the vendor's position is that the issue report cannot be validated because there is no description of an attack
Original NVD description (English source)
Libgcrypt before 1.7.10 and 1.8.x before 1.8.3 allows a memory-cache side-channel attack on ECDSA signatures that can be mitigated through the use of blinding during the signing process in the _gcry_ecc_ecdsa_sign function in cipher/ecc-ecdsa.c, aka the Return Of the Hidden Number Problem or ROHNP. To discover an ECDSA key, the attacker needs access to either the local machine or a different virtual machine on the same physical host.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS