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StrongswanApplication

CVE-2008-4551

MEDIUM · 5.0 CVSS v2.0 Published 2008-10-14
Fix available
A fix is available. Upgrade to after 4.2.6 or later.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
strongSwan 4.2.6 and earlier allows remote attackers to cause a denial of service (daemon crash) via an IKE_SA_INIT message with a large number of NULL values in a Key Exchange payload, which triggers a NULL pointer dereference for the return value of the mpz_export function in the GNU Multiprecision Library (GMP).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In strongSwan 4.2.6 and earlier, a remote attacker can send a specially crafted IKE_SA_INIT message containing a Key Exchange payload with an excessive number of NULL values. This causes the GNU Multiprecision Library's mpz_export function to return NULL, resulting in a NULL pointer dereference that crashes the IPSec daemon.

MitigationUpgrade strongSwan to a version newer than 4.2.6. If immediate upgrade is not feasible, consider deploying network-level filtering to block malformed IKE_INIT messages at the perimeter.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
StrongswanApplication
Affected:<= 4.2.6= 2.0.0= 2.0.1= 2.0.2= 2.1.0= 2.1.1= 2.1.2= 2.1.3= 2.1.4= 2.1.5= 2.2.0= 2.2.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/A:P

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed strongSwan version
    Run 'ipsec --version' or check package manager (dpkg -l | grep strongswan, rpm -qa | grep strongswan)
    Affected if Version is 4.2.6 or earlier, or one of: 2.0.0, 2.0.1, 2.0.2, 2.1.0, 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.1.5, 2.2.0, 2.2.1
  2. Confirm IKE daemon is active
    Run 'ipsec status' or check process list for 'charon' or 'pluto' daemon
    Affected if IKE daemon is running and handling IKE_SA_INIT messages
  3. Verify IKE service exposure
    Check if UDP ports 500 and 4500 are listening (netstat -ulnp | grep -E '500|4500' or ss -ulnp)
    Affected if IKE ports are accessible from untrusted networks, enabling remote attackers to send malformed IKE_SA_INIT messages

Your environment is affected if strongSwan version is 4.2.6 or earlier (or any listed 2.x version) AND the IKE daemon is running with exposed UDP ports 500/4500.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 4.2.6
Interim mitigation

Upgrade strongSwan to a version newer than 4.2.6. If immediate upgrade is not feasible, consider deploying network-level filtering to block malformed IKE_INIT messages at the perimeter.

Fix this in Strongswan Scoped from the published advisory
  • Consultation3.0 h
  • Implementation3.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,400
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,840.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2008-4551 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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