Denial of Service (DoS) Affecting std/net/http package, versions <1.25.13>=1.26.0-0 <1.26.6>=1.27.0-0 <1.27.0-rc.3
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published16 Aug 2026
- disclosed13 Aug 2026
- creditUnknown
Introduced: 13 Aug 2026
NewCVE-2026-56853 (opens in a new tab)How to fix?
Upgrade std/net/http to version 1.25.13, 1.26.6, 1.27.0-rc.3 or higher.
Overview
std/net/http is a Go standard library package std/net/http
Affected versions of this package are vulnerable to Denial of Service (DoS).
Go Vulnerability Report:
When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.
Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.
One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.
When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.
Two common types of DoS vulnerabilities:
High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.
Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm
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