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Findings

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 t…

Published Jun 8, 2021 · updated Oct 14, 2026 · gnupg libgcrypt

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.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 8, 2021 · NIST NVD

    Detected

    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.

  2. Oct 14, 2026 · NIST NVD

    Updated

    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.

Affected

  • cpe debian/debian linux9.0
  • cpe fedoraproject/fedora33
  • cpe fedoraproject/fedora34
  • cpe gnupg/libgcryptversion unspecified
  • cpe oracle/communications cloud native core binding support function1.11.0
  • cpe oracle/communications cloud native core network function cloud native environment1.10.0
  • cpe oracle/communications cloud native core network function cloud native environment1.9.0

Sources

  • CVE.orgVulnerability recordCVE-2021-33560

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-33560

    30-day exploitation probability 2.4%

    first.org
  • NIST NVDVulnerability recordCVE-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.

    nvd.nist.gov

References