CVE-2016-6329

Severity: medium (CVSS 5.9 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 5.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2017-01-31 · updated 2026-06-17
Weakness: CWE-200

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.

Affected products

OpenVPN: through 2.3.14

References

http://www-01.ibm.com/support/docview.wss?uid=nas8N1021697
http://www-01.ibm.com/support/docview.wss?uid=swg21991482
http://www-01.ibm.com/support/docview.wss?uid=swg21995039
http://www.securityfocus.com/bid/92631
http://www.securitytracker.com/id/1036695
https://cert-portal.siemens.com/productcert/pdf/ssa-556833.pdf
https://community.openvpn.net/openvpn/wiki/SWEET32
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05369403
https://security.gentoo.org/glsa/201611-02
https://sweet32.info/
http://www-01.ibm.com/support/docview.wss?uid=nas8N1021697
http://www-01.ibm.com/support/docview.wss?uid=swg21991482

Get alerted when CVE-2016-6329 or the next vulnerability affects your stack