CVE-2019-16201 Denial of service in n/a

What is CVE-2019-16201?

CVE-2019-16201 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 26 Nov 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

WEBrick::HTTPAuth::DigestAuth in Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 has a regular expression Denial of Service cause by looping/backtracking. A victim must expose a WEBrick server that uses DigestAuth to the Internet or a untrusted network.

Weakness: CWE-287

Which versions are affected by CVE-2019-16201?

It affects 2 products.

Products include Debian Debian Linux, Ruby-Lang Ruby.

How do I fix CVE-2019-16201?

Upgrade to a fixed version.

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-2019-16201 being exploited?

There is no known exploitation of CVE-2019-16201 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-2019-16201, CLEANSTART-2026-BG69188, DEBIAN-CVE-2019-16201, GHSA-26h5-qgg3-p324, UBUNTU-CVE-2019-16201.