How severe is CVE-2016-6329?

CVE-2016-6329 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2016-6329 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-6329?

CVE-2016-6329 affects Openvpn. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-6329?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2016-6329 published?

CVE-2016-6329 was published on 2017-01-31 and last updated on 2026-06-17.

CVE-2016-6329

CVE-2016-6329 is a medium-severity vulnerability in Openvpn with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 6% (92nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Openvpn
Published: 2017-01-31
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2016-6329?: 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.
How severe is CVE-2016-6329?: CVE-2016-6329 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2016-6329 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6329?: CVE-2016-6329 affects Openvpn. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-6329?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2016-6329 published?: CVE-2016-6329 was published on 2017-01-31 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:openvpn:openvpn:*:*:*:*:*:*:*:*

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