IKEv1 protocol is vulnerable to DoS amplification attack
Published Jun 16, 2016
7.5
HIGHCVSS 3.0
EPSS 2.70%
Description
programs/pluto/ikev1.c in libreswan before 3.17 retransmits in initial-responder states, which allows remote attackers to cause a denial of service (traffic amplification) via a spoofed UDP packet. NOTE: the original behavior complies with the IKEv1 protocol, but has a required security update from the libreswan vendor; as of 2016-06-10, it is expected that several other IKEv1 implementations will have vendor-required security updates, with separate CVE IDs assigned to each.
Affected products
No data.
No data.
Red Hat Enterprise Linux 7
libreswan-0:3.15-8.el7
Fixed · RHSA-2016:2603
Red Hat Enterprise Linux 5
ipsec-tools
Will not fix
Red Hat Enterprise Linux 5
openswan
Will not fix
Red Hat Enterprise Linux 6
libreswan
Will not fix
Red Hat Enterprise Linux 6
openswan
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 7 | libreswan-0:3.15-8.el7 | Fixed | RHSA-2016:2603 |
| Red Hat Enterprise Linux 5 | ipsec-tools | Will not fix | n/a |
| Red Hat Enterprise Linux 5 | openswan | Will not fix | n/a |
| Red Hat Enterprise Linux 6 | libreswan | Will not fix | n/a |
| Red Hat Enterprise Linux 6 | openswan | Will not fix | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This is a protocol flaw which affects IKEv1. All complaint implementations are therefore affected by this flaw. Red Hat Product Security team, does not consider IKEv2 to be affected. For more details please refer to https://bugzilla.redhat.com/show_bug.cgi?id=1308508#c2
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AV:N/AC:L/Au:N/C:N/I:N/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
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 (12 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 2.70% (0.02702) | 85.41th | v5 (v2026.06.15) |
| Jun 15, 2026 | 2.77% (0.02773) | 84.38th | v5 (v2026.06.15) |
| Mar 30, 2025 | 1.03% (0.01027) | 75.29th | v4 (v2025.03.14) |
| Mar 29, 2025 | 3.35% (0.03354) | 78.70th | v4 (v2025.03.14) |
| Mar 17, 2025 | 1.03% (0.01027) | 75.76th | v4 (v2025.03.14) |
| Dec 12, 2024 | 1.07% (0.01075) | 84.91th | v3 (v2023.03.01) |
| Mar 6, 2024 | 0.91% (0.00912) | 82.37th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.91% (0.00912) | 80.37th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.21% (0.01213) | 66.61th | v2 (v2022.01.01) |
| Feb 17, 2023 | 1.21% (0.01213) | 66.22th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.21% (0.01213) | 64.21th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.21% (0.01213) | 40.54th | v2 (v2022.01.01) |
References (8)
- http://rhn.redhat.com/errata/RHSA-2016-2603.html vendor-advisoryx_refsource_REDHAT
- http://www.openwall.com/lists/oss-security/2016/06/10/4 mailing-listx_refsource_MLIST
- https://access.redhat.com/security/cve/CVE-2016-5361 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1308508 Issue Tracking
- https://github.com/libreswan/libreswan/commit/152d6d95632d8b9477c170f1de99bcd86d7fb1d6 x_refsource_CONFIRMPatchVendor Advisory
- https://lists.libreswan.org/pipermail/swan-dev/2016-March/001394.html mailing-listx_refsource_MLIST
- https://nvd.nist.gov/vuln/detail/CVE-2016-5361
- https://www.cve.org/CVERecord?id=CVE-2016-5361
| Link | Providers | Tags |
|---|---|---|
| http://rhn.redhat.com/errata/RHSA-2016-2603.html | vendor-advisoryx_refsource_REDHAT | |
| http://www.openwall.com/lists/oss-security/2016/06/10/4 | mailing-listx_refsource_MLIST | |
| https://access.redhat.com/security/cve/CVE-2016-5361 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1308508 | Issue Tracking | |
| https://github.com/libreswan/libreswan/commit/152d6d95632d8b9477c170f1de99bcd86d7fb1d6 | x_refsource_CONFIRMPatchVendor Advisory | |
| https://lists.libreswan.org/pipermail/swan-dev/2016-March/001394.html | mailing-listx_refsource_MLIST | |
| https://nvd.nist.gov/vuln/detail/CVE-2016-5361 | ||
| https://www.cve.org/CVERecord?id=CVE-2016-5361 |
Change history (0)
No recorded changes yet.