MEDIUM
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
Published Jan 31, 2017
5.9
MEDIUMCVSS 3.0
EPSS 5.94%
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
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
5.9 MEDIUM NVD
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact None
Availability Impact None
4.3 MEDIUM NVD
AV:N/AC:M/Au:N/C:P/I:N/A:N
Access Vector Network
Access Complexity Medium
Authentication None
Confidentiality Impact Partial
Integrity Impact None
Availability Impact None
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
5.94% 0.05940
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.05940
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (36 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 5.94% (0.05940) | 93.04th | v5 (v2026.06.15) |
| Jun 15, 2026 | 5.94% (0.05940) | 92.31th | v5 (v2026.06.15) |
| Mar 4, 2026 | 5.53% (0.05530) | 90.08th | v4 (v2025.03.14) |
| Mar 1, 2026 | 1.36% (0.01363) | 80.01th | v4 (v2025.03.14) |
| Feb 4, 2026 | 5.53% (0.05530) | 90.02th | v4 (v2025.03.14) |
| Feb 1, 2026 | 1.36% (0.01363) | 79.91th | v4 (v2025.03.14) |
| Jan 4, 2026 | 4.89% (0.04887) | 89.24th | v4 (v2025.03.14) |
| Jan 1, 2026 | 1.75% (0.01747) | 82.15th | v4 (v2025.03.14) |
| Dec 4, 2025 | 4.89% (0.04887) | 89.17th | v4 (v2025.03.14) |
| Dec 1, 2025 | 1.75% (0.01747) | 82.03th | v4 (v2025.03.14) |
| Nov 4, 2025 | 5.51% (0.05509) | 89.78th | v4 (v2025.03.14) |
| Nov 1, 2025 | 1.36% (0.01358) | 79.61th | v4 (v2025.03.14) |
| Oct 4, 2025 | 5.51% (0.05509) | 89.81th | v4 (v2025.03.14) |
| Oct 1, 2025 | 1.36% (0.01358) | 79.56th | v4 (v2025.03.14) |
| Sep 4, 2025 | 5.65% (0.05652) | 90.02th | v4 (v2025.03.14) |
| Sep 1, 2025 | 1.56% (0.01563) | 80.86th | v4 (v2025.03.14) |
| Aug 26, 2025 | 5.51% (0.05509) | 89.85th | v4 (v2025.03.14) |
| Aug 4, 2025 | 8.39% (0.08395) | 91.93th | v4 (v2025.03.14) |
| Aug 1, 2025 | 2.14% (0.02135) | 83.58th | v4 (v2025.03.14) |
| Jul 4, 2025 | 8.39% (0.08395) | 91.88th | v4 (v2025.03.14) |
| Jul 1, 2025 | 2.14% (0.02135) | 83.47th | v4 (v2025.03.14) |
| Jun 4, 2025 | 8.39% (0.08395) | 91.84th | v4 (v2025.03.14) |
| Jun 1, 2025 | 2.14% (0.02135) | 83.39th | v4 (v2025.03.14) |
| May 4, 2025 | 8.39% (0.08395) | 91.82th | v4 (v2025.03.14) |
| May 1, 2025 | 2.14% (0.02135) | 83.29th | v4 (v2025.03.14) |
| Mar 30, 2025 | 8.39% (0.08395) | 91.49th | v4 (v2025.03.14) |
| Mar 29, 2025 | 23.97% (0.23966) | 93.62th | v4 (v2025.03.14) |
| Mar 17, 2025 | 9.05% (0.09049) | 92.01th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.52% (0.00518) | 77.54th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.52% (0.00518) | 76.08th | v3 (v2023.03.01) |
| May 7, 2023 | 0.52% (0.00518) | 73.34th | v3 (v2023.03.01) |
| Mar 29, 2023 | 0.73% (0.00734) | 77.93th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.79% (0.00792) | 78.87th | v3 (v2023.03.01) |
| Mar 6, 2023 | 2.17% (0.02172) | 80.77th | v2 (v2022.01.01) |
| Apr 1, 2022 | 2.17% (0.02172) | 78.91th | v2 (v2022.01.01) |
| Feb 4, 2022 | 2.17% (0.02172) | 57.73th | v2 (v2022.01.01) |
Weaknesses (2)
References (10)
- http://www-01.ibm.com/support/docview.wss?uid=nas8N1021697 x_refsource_CONFIRMPermissions RequiredThird Party Advisory
- http://www-01.ibm.com/support/docview.wss?uid=swg21991482 x_refsource_CONFIRMThird Party Advisory
- http://www-01.ibm.com/support/docview.wss?uid=swg21995039 x_refsource_CONFIRMThird Party Advisory
- http://www.securityfocus.com/bid/92631 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1036695 vdb-entryx_refsource_SECTRACKThird Party AdvisoryVDB Entry
- https://cert-portal.siemens.com/productcert/pdf/ssa-556833.pdf x_refsource_CONFIRM
- https://community.openvpn.net/openvpn/wiki/SWEET32 x_refsource_CONFIRMVendor Advisory
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05369403 x_refsource_CONFIRMThird Party Advisory
- https://security.gentoo.org/glsa/201611-02 vendor-advisoryx_refsource_GENTOOThird Party Advisory
- https://sweet32.info/ x_refsource_MISCTechnical DescriptionThird Party Advisory
| Link | Providers | Tags |
|---|---|---|
| http://www-01.ibm.com/support/docview.wss?uid=nas8N1021697 | x_refsource_CONFIRMPermissions RequiredThird Party Advisory | |
| http://www-01.ibm.com/support/docview.wss?uid=swg21991482 | x_refsource_CONFIRMThird Party Advisory | |
| http://www-01.ibm.com/support/docview.wss?uid=swg21995039 | x_refsource_CONFIRMThird Party Advisory | |
| http://www.securityfocus.com/bid/92631 | vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry | |
| http://www.securitytracker.com/id/1036695 | vdb-entryx_refsource_SECTRACKThird Party AdvisoryVDB Entry | |
| https://cert-portal.siemens.com/productcert/pdf/ssa-556833.pdf | x_refsource_CONFIRM | |
| https://community.openvpn.net/openvpn/wiki/SWEET32 | x_refsource_CONFIRMVendor Advisory | |
| https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05369403 | x_refsource_CONFIRMThird Party Advisory | |
| https://security.gentoo.org/glsa/201611-02 | vendor-advisoryx_refsource_GENTOOThird Party Advisory | |
| https://sweet32.info/ | x_refsource_MISCTechnical DescriptionThird Party Advisory |
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner redhat
Published Jan 31, 2017
Updated Aug 6, 2024
Reserved Jul 26, 2016
Link CVE-2016-6329
CISA Vulnrichment
Updated n/a