Skip to content
Fencer Intel
critical 9.8

CVE-2015-5739 json

Request smuggling due to improper header parsing in net/http

published 9y ago modified 4mo ago also CVE-2015-5740 , CVE-2015-5741 , GO-2021-0159 , EUVD-2015-5685

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
9.6%
EPSS 9.6% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

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."

Patch / fix

  • go stdlib 1.4.3
  • golang RHEL 7 1.6.3-1.el7_2.1
  • golang-bin RHEL 7 1.6.3-1.el7_2.1
  • golang-src RHEL 7 1.6.3-1.el7_2.1
  • golang-misc RHEL 7 1.6.3-1.el7_2.1
  • golang-tests RHEL 7 1.6.3-1.el7_2.1

red hat advisories RHSA-2016:1538

Is CVE-2015-5739 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2015-5739 updated cvss 6.8

golang: HTTP request smuggling in net/http library

  • Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) Operational Tools golang Red Hat OpenStack Platform 8 (Liberty) Operational Tools golang, golang-src, golang-pkg-linux-amd64, golang-pkg-bin-linux-amd64
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux Server Optional (v. 7) golang 1.6.3-1.el7_2.1, golang-bin 1.6.3-1.el7_2.1, golang-src 1.6.3-1.el7_2.1, golang-misc 1.6.3-1.el7_2.1, golang-tests 1.6.3-1.el7_2.1
    fixed: vendor fix RHSA-2016:1538

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

9.63% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected packages

ecosystem package affected fixed in
go stdlib
<1.4.3
1.4.3

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.