CVE-2016-10396: The racoon daemon in IPsec-Tools 0.8.2 contains a remotely exploitable computational-complexity attack when pa

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HIGH 7.5REMOTEDOWNGRADE

CVE-2016-10396 is a high-severity flaw (CVSS 7.5) affecting ipsec-tools. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The racoon daemon in IPsec-Tools 0.8.2 contains a remotely exploitable computational-complexity attack when parsing and storing ISAKMP fragments. The implementation permits a remote attacker to exhaust computational resources on the remote endpoint by repeatedly sending ISAKMP fragment packets in a particular order such that the worst-case computational complexity is realized in the algorithm utilized to determine if reassembly of the fragments c

Why this priority

High severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.9% (top 13%)
CISA exploited list	No
Weakness	CWE-407
Published	2017-07-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: ipsec-tools

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2017-07-06 01:29 UTCPublished CVE record published
2026-06-17 00:39 UTCUpdated Record last modified

ipsec-tools ipsec-tools DOWNGRADE

Affected: 0.8.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.8.2

1. Check installed version

apt-cache policy ipsec-tools || rpm -q ipsec-tools || ipsec-tools --version

2. No fixed release: DOWNGRADE to a release before 0.8.2 (Debian / Ubuntu)

apt-cache madison ipsec-tools sudo apt install ipsec-tools=<VERSION_BEFORE_0.8.2> sudo apt-mark hold ipsec-tools

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ipsec-tools sudo dnf downgrade ipsec-tools-<VERSION_BEFORE_0.8.2> sudo dnf versionlock add ipsec-tools

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2016-10396?

ipsec-tools: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2016-10396 being exploited?

CVE-2016-10396 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2016-10396 affect?

CVE-2016-10396 affects ipsec-tools. Severity is high (CVSS 7.5). The racoon daemon in IPsec-Tools 0.8.2 contains a remotely exploitable computational-complexity attack when parsing and storing ISAKMP fragments. The implementation permits a remote attacker to exhaust computational resources on the remote

How urgent is CVE-2016-10396?

Priority 53/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2015-4047 HIGH 7.8 DOWNGRADE MITIGATE racoon/gssapi.c in IPsec-Tools 0.8.2 allows remote attackers to cause a denial of service (NULL pointer derefe

References

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