CVE-2021-3580 Denial of service in nettle

What is CVE-2021-3580?

CVE-2021-3580 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 5 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A flaw was found in the way nettle's RSA decryption functions handled specially crafted ciphertext. An attacker could use this flaw to provide a manipulated ciphertext leading to application crash and denial of service.

Weakness: CWE-20

Which versions are affected by CVE-2021-3580?

It affects 4 products.

Products include Debian Debian Linux, Netapp Ontap Select Deploy Administration Utility, Nettle Project Nettle, Redhat Enterprise Linux.

How do I fix CVE-2021-3580?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-3580 being exploited?

There is no known exploitation of CVE-2021-3580 in the wild and no public exploit code.

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-2021-3580, AZL-6741, CLSA-2026-1777451834, CLSA-2026-1777452099, CLSA-2026-1790604865, DEBIAN-CVE-2021-3580 and 8 more.