Uncontrolled Recursion Affecting std/net/http package, versions <1.15.12>=1.16.0-0 <1.16.4
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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- published6 Jan 2026
- disclosed15 Jul 2022
- creditGuido Vranken
Introduced: 15 Jul 2022
CVE-2021-31525 (opens in a new tab)How to fix?
Upgrade std/net/http to version 1.15.12, 1.16.4 or higher.
Overview
std/net/http is a Go standard library package std/net/http
Affected versions of this package are vulnerable to Uncontrolled Recursion.
Go Vulnerability Report:
A malicious HTTP server or client can cause the net/http client or server to panic.ReadRequest and ReadResponse can hit an unrecoverable panic when reading a very large header (over 7MB on 64-bit architectures, or over 4MB on 32-bit ones). Transport and Client are vulnerable and the program can be made to crash by a malicious server. Server is not vulnerable by default, but can be if the default max header of 1MB is overridden by setting Server.MaxHeaderBytes to a higher value, in which case the program can be made to crash by a malicious client.This also affects golang.org/x/net/http2/h2c and HeaderValuesContainsToken in golang.org/x/net/http/httpguts.