CVE-2021-28662 Denial of service in n/a

What is CVE-2021-28662?

CVE-2021-28662 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 27 May 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

An issue was discovered in Squid 4.x before 4.15 and 5.x before 5.0.6. If a remote server sends a certain response header over HTTP or HTTPS, there is a denial of service. This header can plausibly occur in benign network traffic.

Weakness: CWE-116

Which versions are affected by CVE-2021-28662?

It affects 3 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Squid-Cache Squid.

How do I fix CVE-2021-28662?

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-2021-28662 being exploited?

There is no known exploitation of CVE-2021-28662 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-2021-28662, DEBIAN-CVE-2021-28662, GHSA-jjq6-mh2h-g39h, UBUNTU-CVE-2021-28662.