CVE-2020-27813 Integer overflow in github.com/gorilla/websocket

What is CVE-2020-27813?

CVE-2020-27813 is a high-severity vulnerability in Debian Debian Linux, published on 2 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An integer overflow vulnerability exists with the length of websocket frames received via a websocket connection. An attacker would use this flaw to cause a denial of service attack on an HTTP Server allowing websocket connections.

Weakness: CWE-400, CWE-190

Which versions are affected by CVE-2020-27813?

3 open source packages ship an affected version, including github.com/gorilla/websocket. It affects 2 products.

Products include Debian Debian Linux, Gorillatoolkit Websocket.

How do I fix CVE-2020-27813?

Upgrade github.com/gorilla/websocket to 1.4.1 or later.

Is CVE-2020-27813 being exploited?

There is no known exploitation of CVE-2020-27813 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
• GitHub advisory
• How this page is made

Also known as DLA-2520-1, DLA-3420-1, GHSA-3xh2-74w9-5vxm, GHSA-jf24-p9p9-4rjh, GO-2020-0019, RHSA-2021:0833 and 2 more.