CVE-2026-8646
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 · uneditedIBM WebSphere Application Server 9.0 and 8.5 and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.6 are vulnerable to HTTP request smuggling. A remote attacker could smuggle a specially crafted request to the application server thereby allowing the attacker to bypass security controls, spoof identity, escalate privilege, and expose sensitive information.
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 · moderate confidenceIBM WebSphere Application Server (traditional and Liberty) is vulnerable to HTTP request smuggling due to inconsistent parsing of HTTP headers (typically Content-Length and Transfer-Encoding) between front-end proxies and the backend application server. Attackers can craft specially malformed requests that get interpreted differently by intermediate components, allowing them to bypass security controls, inject malicious requests, and access sensitive 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>= 8.5.0.0, < 8.5.5.30>= 9.0.0.0, < 9.0.5.29>= 17.0.0.3, < 26.0.0.7CVSS 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
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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 WebSphere Application Server versionFor traditional: check the install directory for version.info or run 'java -version' and look at the product directory. For Liberty: check the 'wlp/lib/versions' directory or the 'server.xml' for the version attribute.Affected if The installed version falls within 8.5.0.0-8.5.5.29, 9.0.0.0-9.0.5.28, or 17.0.0.3-26.0.0.6
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Confirm WebSphere deployment architectureInspect network topology and configuration to determine if a front-end proxy (such as IBM HTTP Server, IHS, or third-party reverse proxy) sits in front of the WebSphere Application Server processing client requests.Affected if A front-end proxy exists in front of WebSphere, as the smuggling attack requires inconsistent parsing between proxy and backend.
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Check HTTP pipelining configurationReview server.xml (Liberty) or http.conf/IHS configuration for HTTP pipelining enablement settings, or test if the server accepts multiple requests on a single connection without waiting for responses.Affected if HTTP pipelining is enabled on the proxy or backend, allowing multiple requests to be sent consecutively.
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Verify Content-Length and Transfer-Encoding header handlingSend a test request with both Content-Length and Transfer-Encoding headers present to see how the server parses and prioritizes them, or review proxy and WebSphere logs for inconsistent handling patterns.Affected if The server accepts and processes requests with conflicting Content-Length and Transfer-Encoding headers, or the proxy and backend interpret them differently.
Your environment is affected if WebSphere version is below 8.5.5.30, 9.0.5.29, or 26.0.0.7 AND a front-end proxy exists that could interpret HTTP headers differently from the backend server.
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 · scoped8.5.5.309.0.5.2926.0.0.7
Apply IBM's security patches for WebSphere Application Server 9.0, 8.5, and Liberty (versions 17.0.0.3 through 26.0.0.6). Ensure front-end proxies and application servers parse HTTP headers consistently, and disable HTTP pipelining where possible.
IBM WebSphere Application Server 8.5.5.30, 9.0.5.29, or 26.0.0.7 (depending on your product line)
- 1. Identify the currently installed IBM WebSphere Application Server version by checking the installation directory or using the versionInfo command
- 2. For WebSphere Application Server 8.5.x: Plan upgrade to version 8.5.5.30 or later
- 3. For WebSphere Application Server 9.0.x: Plan upgrade to version 9.0.5.29 or later
- 4. For WebSphere Application Server Liberty 17.0.0.3 through 26.0.0.6: Plan upgrade to version 26.0.0.7 or later
- 5. Review IBM's official fix central or installation documentation for the specific upgrade procedure for your deployment type
- 6. Test the upgrade in a non-production environment before deploying to production
- 7. Apply the upgrade following IBM's recommended migration path
- 8. Verify the HTTP request smuggling vulnerability is remediated by reviewing IBM's security bulletin for this CVE
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-8646 — 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-2026-8646 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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