CVE-2021-33560 Weak cryptography in n/a

What is CVE-2021-33560?

CVE-2021-33560 is a high-severity vulnerability in Debian Debian Linux, published on 8 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-203, CWE-325

Which versions are affected by CVE-2021-33560?

It affects 8 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Gnupg Libgcrypt, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Network Function Cloud Native Environment, Oracle Communications Cloud Native Core Network Repository Function and 2 more.

How do I fix CVE-2021-33560?

Upgrade to a fixed version.

Is CVE-2021-33560 being exploited?

There is no known exploitation of CVE-2021-33560 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2021-33560, ALSA-2021:4409, DEBIAN-CVE-2021-33560, GHSA-g9p5-p7h5-p2wg, JLSEC-2026-123, MGASA-2021-0294 and 11 more.