Description
The net/http library in net/textproto/reader.go in Go before 1.4.3 does not properly parse HTTP header keys, which allows remote attackers to conduct HTTP request smuggling attacks via a space instead of a hyphen, as demonstrated by "Content Length" instead of "Content-Length."
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | gccgo-4.9 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | golang +5 | 1.6.3-1.el7_2.1 | RHSA-2016:1538 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | stdlib | < 1.4.3 | 1.4.3 | GO-2021-0159 |
Advisories 1
- RHSA-2016:1538 Red Hat Security Advisory: golang security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · May 13, 2026
References
- [oss-security] 20150804 CVE Request - Go net/http library - HTTP smuggling mailing-list
- FEDORA-2015-15619 vendor-advisory
- FEDORA-2015-15618 vendor-advisory
- RHSA-2016:1538 vendor-advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1250352
- [oss-security] 20150805 Re: CVE Request - Go net/http library - HTTP smuggling mailing-list
- [oss-security] 20150729 CVE Request - Go net/http library - HTTP smuggling mailing-list
- 76281 vdb-entry
- https://github.com/golang/go/commit/117ddcb83d7f42d6aa72241240af99ded81118e9