What is CVE-2015-5741?

CVE-2015-5741 is a critical-severity vulnerability in Golang Go, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.8/10. Published 2020-02-08.

How severe is CVE-2015-5741?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2015-5741 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Golang Go

CVE-2015-5741

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 that contains Content-Length and Transfer-Encoding header fields.

Vulnerability class: HTTP Request Smuggling

Published 2020-02-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.027 (85.8th percentile), scored 2026-10-19.

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 85.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.027 · newest: 0.027 · change: 0.000

Affected products

Golang Go
Red Hat Enterprise Linux — versions 7.0
Red Hat OpenStack — versions 7.0, 8

Weakness classification (CWE)

CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

Public proof-of-concept exploits

References

seclists.org/oss-sec/2015/q3/237 (Mailing List, Third Party Advisory)
seclists.org/oss-sec/2015/q3/292 (Mailing List, Third Party Advisory)
seclists.org/oss-sec/2015/q3/294 (Mailing List, Third Party Advisory)
bugzilla.redhat.com/show_bug.cgi (Patch, Third Party Advisory, Issue Tracking)
github.com/golang/go/commit/300d9a21583e7cf0149a778a0611e76ff7c6680f (Patch, Third Party Advisory)
lists.fedoraproject.org/pipermail/package-announce/2015-October/168029.html (Patch, Mailing List, Third Party Advisory)
lists.fedoraproject.org/pipermail/package-announce/2015-October/167997.html (Patch, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2015-5741?: CVE-2015-5741 is a critical-severity vulnerability in Golang Go, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.8/10. Published 2020-02-08.
How severe is CVE-2015-5741?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2015-5741 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.