CVE-2026-34417
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 · uneditedOSCAL-GUI contains a reflected cross-site scripting vulnerability that allows unauthenticated attackers to execute arbitrary JavaScript in a victim's browser by injecting malicious content through the project request parameter in oscal-forms.php. The parameter value is URL-decoded and assigned to the project_id variable without sanitization in oscal-functions.php, and when the supplied project ID is not found, the unsanitized value is concatenated into an error message via the Messages() function and reflected into the HTML response body without encoding.
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 confidenceOSCAL-GUI has a reflected cross-site scripting (XSS) vulnerability in oscal-forms.php where the project request parameter is URL-decoded and assigned to project_id without sanitization in oscal-functions.php. When the supplied project ID is not found, the unsanitized value is concatenated into an error message via the Messages() function and reflected into the HTML response body without proper encoding, allowing execution of arbitrary JavaScript in victim browsers.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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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Confirm OSCAL-GUI is installedIdentify if the OSCAL-GUI web application is present in your environment by checking for its web directories, source files, or by inspecting HTTP responses from the application for OSCAL-GUI branding.Affected if OSCAL-GUI is present in the environment
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Locate oscal-functions.phpSearch for the file oscal-functions.php in the OSCAL-GUI installation directory, typically found in the application root or includes folder.Affected if The file oscal-functions.php exists in the OSCAL-GUI installation
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Identify OSCAL-GUI versionCheck version files, composer.json, or any version declaration within the OSCAL-GUI source code to determine the installed version.Affected if The installed version cannot be determined or falls within an affected range (if known)
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Verify project_id parameter handlingInspect oscal-functions.php for code that handles the project_id request parameter, specifically looking for URL-decoding operations and usage in the Messages() function.Affected if The code shows project_id is URL-decoded and passed to Messages() without sanitization
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Test error message reflectionSend an HTTP request to the OSCAL-GUI application with a crafted project_id parameter containing non-existent values (such as <script>alert(1)</script>) and observe if the value is reflected in an error message without HTML encoding.Affected if The project_id value is reflected in an error message without being HTML-encoded
You are affected if OSCAL-GUI is installed and the project_id parameter is reflected in error messages without HTML encoding.
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.
From vendor dataImplement proper input validation and output encoding: sanitize the project_id parameter before use, and apply HTML entity encoding to all user-supplied data before reflecting it in error messages via the Messages() function.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
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Free · runs locallyCheck whether your project pulls in CVE-2026-34417 — 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-2026-34417 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data