CVE-2016-6329

Name: CVE-2016-6329
Creator: NVD / NIST
Published: 2017-01-31T22:59:00.377+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 5.94%

Last modified Jun 17, 2026

CVE-2016-6329 is a vulnerability of currently unknown severity. OpenVPN, when using a 64-bit block cipher, makes it easier for remote attackers to obtain cleartext data via a birthday attack against a long-duration encrypted session, as demonstrated by an HTTP-over-OpenVPN session using Blowfish in CBC mode, aka a "Sweet32" attack.. EPSS estimates a 5.94% chance of exploitation in the next 30 days.

Description

OpenVPN, when using a 64-bit block cipher, makes it easier for remote attackers to obtain cleartext data via a birthday attack against a long-duration encrypted session, as demonstrated by an HTTP-over-OpenVPN session using Blowfish in CBC mode, aka a "Sweet32" attack.

Metrics

EPSS Probability

5.94%

92.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Openvpn	Openvpn	<= 2.3.14

References

http://www-01.ibm.com/support/docview.wss?uid=nas8N1021697Permissions Required, Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg21991482Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg21995039Third Party Advisory
http://www.securityfocus.com/bid/92631Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1036695Third Party Advisory, VDB Entry
https://cert-portal.siemens.com/productcert/pdf/ssa-556833.pdf
https://community.openvpn.net/openvpn/wiki/SWEET32Vendor Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05369403Third Party Advisory
https://security.gentoo.org/glsa/201611-02Third Party Advisory
https://sweet32.info/Technical Description, Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=nas8N1021697Permissions Required, Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg21991482Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg21995039Third Party Advisory
http://www.securityfocus.com/bid/92631Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1036695Third Party Advisory, VDB Entry
https://cert-portal.siemens.com/productcert/pdf/ssa-556833.pdf
https://community.openvpn.net/openvpn/wiki/SWEET32Vendor Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05369403Third Party Advisory
https://security.gentoo.org/glsa/201611-02Third Party Advisory
https://sweet32.info/Technical Description, Third Party Advisory

Timeline

Published: Jan 31, 2017
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2016-6329?

How severe is CVE-2016-6329?

Severity scoring for CVE-2016-6329 is pending analysis. The EPSS model estimates a 5.94% probability of exploitation in the next 30 days.

How do I fix CVE-2016-6329?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2016-6329?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST