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CVE-2015-5739

32
FAUCET Score

CVE-2015-5739 describes a critical HTTP request smuggling vulnerability in the net/http library of Go before version 1.4.3, affecting products like Fedora and Red Hat. The flaw stems from improper parsing of HTTP header keys, allowing attackers to substitute spaces for hyphens (e.g., "Content Length" instead of "Content-Length"). With a CVSS score of 9.8 (Critical), this vulnerability is easily exploitable over the network with no user interaction, leading to high impacts on confidentiality, integrity, and availability. Despite its severity, there is no evidence of active exploitation, publicly available exploit code, or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.4.2CPE matchmatch criteria
cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*
21CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:21:*:*:*:*:*:*:*
22CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:22:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
7.2CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux_server_aus:7.2:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

9.8CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
9.63%
Probability of exploitation in next 30 days
EPSS Percentile
95.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0963 is in the 90th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (5)

github_advisorypatch availablevia nvd_reference
View patch
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: golang-0:1.6.3-1.el7_2.1
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) Operational ToolsFixed in: golang
redhatend of lifevia redhat_api
Product: Red Hat OpenStack Platform 8 (Liberty) Operational ToolsFixed in: golang

Vendor Advisories (1)

redhatCVE-2015-5739Moderate

golang: HTTP request smuggling in net/http library

Jul 29, 2015

References

lists.fedoraproject.org / pipermail/package-announce/2015-October/167997.html
Third Party Advisory
lists.fedoraproject.org / pipermail/package-announce/2015-October/168029.html
Third Party Advisory
rhn.redhat.com / errata/RHSA-2016-1538.html
Third Party Advisory
bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
seclists.org / oss-sec/2015/q3/237
Mailing ListThird Party Advisory
seclists.org / oss-sec/2015/q3/292
Mailing ListThird Party Advisory
seclists.org / oss-sec/2015/q3/294
Mailing ListThird Party Advisory
github.com / golang/go/commit/117ddcb83d7f42d6aa72241240af99ded81118e9
Issue TrackingPatchThird Party Advisory
securityfocus.com / bid/76281
Third Party AdvisoryVDB Entry