Public proof of concept

CVE-2016-3959

A public proof of concept exists; no exploitation attested.

Published2016-05-23
WeaknessCWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2016-05-2319:59CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2016-3959?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2016-3959?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Fedoraproject fedora

Branch	Affected	Fixed in	Source
22.x	= 22	no fix published	NVD
23.x	= 23	no fix published	NVD
24.x	= 24	no fix published	NVD

Branch	Affected	Fixed in	Source
1.6	= 1.6	no fix published	NVD
1.5	≤ 1.5	no fix published	NVD

Opensuse leap

Branch	Affected	Fixed in	Source
42.1	= 42.1	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

No fix published by the sources we read yet. NVD record

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedalexmullins/dsa

Sources

NVDCVSS 3.07.5read 2026-10-23
NVDCVSS 2.05read 2026-10-23
NVDweakness (CWE)CWE-20read 2026-10-23
FIRST EPSSEPSS score4.4 %2026-10-22
PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2016-05-23
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2016-3959?

Is CVE-2016-3959 actively exploited?

Active exploitation of CVE-2016-3959 has not been confirmed. Its EPSS score was 4.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2016-3959?

CVE-2016-3959 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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