GO-2022-0761 CVE-2016-5386

Improper input validation in net/http and net/http/cgi

Not rated yet Go

Severity: Not rated yet; No source has published a CVSS score yet
Exploit chance (EPSS): 5.22%; Chance of exploitation in the next 30 days. Higher than 92.51% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: —; Not classified
Fix: 1.6.3; Upgrade stdlib to this version or later

Description

An input validation flaw in the CGI components allows the HTTP_PROXY environment variable to be set by the incoming Proxy header, which changes where Go by default proxies all outbound HTTP requests.

This environment variable is also used to set the outgoing proxy, enabling an attacker to insert a proxy into outgoing requests of a CGI program.

Read more about "httpoxy" here: https://httpoxy.org.

Affected versions

Go

Package	Vulnerable	Fixed in
stdlib	`< 1.6.3`	`1.6.3`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

stdlib Go → `1.6.3`

go

go get stdlib@v1.6.3 && go mod tidy

References

Fixes and patches

Issue reports

go.dev/issue/16405

Timeline

Aug 9, 2022 Published
May 20, 2024 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-4374-p667-p6c8 HTTP/2 rapid reset can cause excessive work in net/http	High Known exploited	Also affects stdlib
CVE-2020-0601 Certificate validation bypass on Windows in crypto/x509	High Known exploited	Also affects stdlib
RUSTSEC-2026-0382 Distrust compromised intermediate certificates in crypto/x509	Medium	Also affects stdlib
GO-2026-6613 HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http	High	Also affects stdlib
GO-2026-6609 Lack of limit on size of parsed Range headers in net/http	High	Also affects stdlib
GO-2026-6608 Memory limit bypass when parsing MIME headers in net/textproto, mime/multipart	High	Also affects stdlib
GO-2026-6607 Reject malformed ECH outer extension references in crypto/tls	High	Also affects stdlib
GO-2026-6604 Root.Mkdir(All) can follow junctions out of the root on Windows in os	Critical	Also affects stdlib

Credits: Dominic Scheirlinck

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