CVE-2026-9561
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 · uneditedEclipse Kura versions prior to 5.6.2 trust the client-supplied X-Forwarded-For HTTP header as the authoritative source of the client IP address in audit log entries. The org.eclipse.kura.web2 (Web Console) and org.eclipse.kura.rest.provider (REST API) components use this header as the primary IP source when initializing audit context, and org.eclipse.kura.jetty.customizer unconditionally installs Jetty's ForwardedRequestCustomizer on all HTTP/HTTPS connectors, causing HttpServletRequest.getRemoteAddr() to reflect the attacker-controlled header value. An unauthenticated remote attacker can exploit this vulnerability to bypass IP-based brute-force protections — such as fail2ban — by spoofing the logged IP address to a non-routable value, allowing a brute-force attack to proceed undetected, or to cause a denial of service against a third party by injecting a victim's IP address and triggering a ban on that address.
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 confidenceEclipse Kura prior to 5.6.2 unconditionally trusts the X-Forwarded-For HTTP header as the authoritative source for client IP addresses. The ForwardedRequestCustomizer is installed on all HTTP/HTTPS connectors, causing HttpServletRequest.getRemoteAddr() to return the attacker-controlled header value instead of the actual client IP. This allows unauthenticated attackers to spoof their source IP in audit logs and bypass IP-based security controls.
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>= 5.0.0, < 5.6.2CVSS 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
- High
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
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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Determine installed Eclipse Kura versionCheck the version of Eclipse Kura running in your environment using the Kura web UI, API, or packaging metadata (e.g., kura.version property in configuration files).Affected if The installed version is prior to 5.6.2 (e.g., 5.6.1, 5.6.0, 5.5.x, or earlier).
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Inspect HTTP connector configurationExamine the Jetty HTTP/HTTPS connector configuration files or the kura.configuration file for any ForwardedRequestCustomizer settings. Look for entries containing 'ForwardedRequestCustomizer' or similar proxy header handling configurations.Affected if ForwardedRequestCustomizer is explicitly added to the connector configuration for any HTTP/HTTPS endpoint.
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Verify X-Forwarded-For header handlingSend a test HTTP request to the Kura web interface with a custom X-Forwarded-For header (e.g., X-Forwarded-For: 1.2.3.4) and inspect the server-side logs or audit records to see which IP address is recorded.Affected if The audit logs or remote address detection shows the value from the X-Forwarded-For header rather than the actual client IP address.
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Check for IP-based security controlsReview any IP-based access control lists, rate limiting rules, or firewall configurations that rely on HttpServletRequest.getRemoteAddr() to identify clients.Affected if The system relies on getRemoteAddr() for IP-based security decisions and the Kura version is below 5.6.2.
You are affected if Eclipse Kura version is below 5.6.2 and the ForwardedRequestCustomizer is active, causing X-Forwarded-For header values to override the actual client IP in logs and security controls.
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 · scoped5.6.2
Upgrade to Eclipse Kura 5.6.2 or later. Alternatively, configure Jetty connectors to not use ForwardedRequestCustomizer or implement strict validation of X-Forwarded-For headers with rejection of untrusted values.
Eclipse Kura 5.6.2
- Upgrade Eclipse Kura to version 5.6.2 or later to remediate the X-Forwarded-For header spoofing vulnerability
- After upgrading, verify that the X-Forwarded-For header is no longer trusted as the authoritative source for client IP addresses in audit logs
- Test IP-based brute-force protections (such as fail2ban) to confirm they function correctly with the new version
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-9561 — 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-2026-9561 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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