What is CVE-2016-3959?

CVE-2016-3959 is a high-severity vulnerability in Golang Go, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2016-05-23.

How severe is CVE-2016-3959?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2016-3959 known to be exploited?

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

Improper input validation in Golang Go

CVE-2016-3959

The Verify function in crypto/dsa/dsa.go in Go before 1.5.4 and 1.6.x before 1.6.1 does not properly check parameters passed to the big integer library, which might allow remote attackers to cause a denial of service (infinite loop) via a crafted public key to a program that uses HTTPS client certificates or SSH server libraries.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2016-05-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.044 (91.0th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 91st percentile — 91.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.044 · newest: 0.044 · change: 0.000

Affected products

Golang Go — versions 1.6
Fedoraproject Fedora — versions 22, 23, 24
openSUSE Leap — versions 42.1

Weakness classification (CWE)

CWE-20 — Improper Input Validation

Public proof-of-concept exploits

References

www.openwall.com/lists/oss-security/2016/04/05/2 (mailing-list)
go-review.googlesource.com/
rhn.redhat.com/errata/RHSA-2016-1538.html (vendor-advisory)
lists.fedoraproject.org/pipermail/package-announce/2016-April/182526.html (vendor-advisory)
groups.google.com/forum/ (mailing-list)
lists.fedoraproject.org/pipermail/package-announce/2016-April/183106.html (vendor-advisory)
lists.opensuse.org/opensuse-updates/2016-05/msg00077.html (vendor-advisory)
www.openwall.com/lists/oss-security/2016/04/05/1 (mailing-list)
lists.fedoraproject.org/pipermail/package-announce/2016-April/183137.html (vendor-advisory)

Frequently asked questions

What is CVE-2016-3959?: CVE-2016-3959 is a high-severity vulnerability in Golang Go, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2016-05-23.
How severe is CVE-2016-3959?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2016-3959 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.