Ubuntu LinuxOperating system · Canonical
CVE-2022-40617
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 · uneditedstrongSwan before 5.9.8 allows remote attackers to cause a denial of service in the revocation plugin by sending a crafted end-entity (and intermediate CA) certificate that contains a CRL/OCSP URL that points to a server (under the attacker's control) that doesn't properly respond but (for example) just does nothing after the initial TCP handshake, or sends an excessive amount of application data.
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 confidenceThe strongSwan revocation plugin before version 5.9.8 is vulnerable to denial of service when processing crafted end-entity or intermediate CA certificates containing malicious CRL/OCSP URLs. Attackers can point these URLs to servers they control that either hang after the TCP handshake or send excessive application data, causing the revocation checking to hang or consume excessive resources.
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
Ubuntu LinuxOperating system
= 14.04= 16.04= 18.04= 20.04= 22.04
Debian LinuxOperating system
= 10.0= 11.0
FedoraOperating system
= 37< 5.9.8>= 3.11.1, < 3.11.20>= 4.3.1, < 4.3.15>= 4.5.1, < 4.6.0CVSS 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
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 checksWork through these to decide whether this CVE applies to you.
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Identify strongSwan installation and versionRun `ipsec --version` or check the package version using your system's package manager (e.g., `dpkg -l | grep strongswan`, `rpm -q strongswan`, or `apt list --installed | grep strongswan`)Affected if The installed version is lower than 5.9.8 (e.g., 5.9.7, 5.9.6, etc.) or the version cannot be determined and the package is installed on an affected Ubuntu/Debian/Fedora system
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Verify the revocation plugin is loadedCheck if the revocation plugin is enabled in the strongSwan configuration files (strongswan.conf, swanctl.conf) or run `ipsec statusall` to see loaded plugins. Look for lines containing 'revocation' in the plugin list.Affected if The revocation plugin appears in the list of loaded plugins or is explicitly enabled in configuration files
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Confirm CRL/OCSP checking is actively configuredInspect the IPsec configuration (ipsec.conf, swanctl.conf) for 'revocation' settings, 'crl' or 'ocsp' policy statements, or certificate validation policies that include revocation checksAffected if Configuration files contain revocation checking policies (e.g., 'crlcheck=1', 'ocspcheck=1', or 'revocation=yes') for end-entity or CA certificates
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Check for active CRL distribution points in deployed certificatesReview any deployed CA or end-entity certificates for embedded CRL Distribution Points (CDP) or Authority Information Access (AIA) fields pointing to OCSP responders. Use `openssl x509 -in <cert.pem> -noout -text` to inspect certificate details.Affected if Certificates deployed to the VPN gateway contain CRL/OCSP URLs and revocation checking is enabled, making the system vulnerable to malicious URL-based resource exhaustion
A system is affected if it runs strongSwan with a version below 5.9.8, has the revocation plugin loaded, and has CRL/OCSP revocation checking enabled for certificates that may contain attacker-controlled URLs.
Generated from the published advisory. Verify against your own configuration.
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.
dbcve · scoped3.11.204.3.154.6.0
Update strongSwan to version 5.9.8 or later to patch the vulnerability. If immediate patching is not feasible, consider disabling the revocation plugin or implementing network-level controls to restrict outgoing connections from the VPN gateway to untrusted CRL/OCSP servers.
strongSwan 5.9.8 or later
- 1. Identify the current strongSwan version installed: `ipsec --version` or check via package manager (e.g., `dpkg -l | grep strongswan` or `rpm -qa | grep strongswan`)
- 2. For Debian/Ubuntu: Update package lists with `sudo apt-get update`
- 3. For Debian/Ubuntu: Upgrade strongSwan with `sudo apt-get install strongswan --upgrade` or `sudo apt-get install strongswan-pki strongswan-libcharon`
- 4. For Fedora: Run `sudo dnf update strongswan`
- 5. Verify the upgrade was successful by checking the version: `ipsec --version`
- 6. Ensure version 5.9.8 or later is installed
- 7. Restart the ipsec service: `sudo ipsec restart` or `sudo systemctl restart strongswan`
- 8. For Ubuntu/Debian: If the package is not available in repositories, consider adding the official strongSwan repository or building from source
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Ubuntu Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-40617 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2022-40617 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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