CVE-2026-35490
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 · uneditedchangedetection.io is a free open source web page change detection tool. Prior to 0.54.8, the @login_optionally_required decorator is placed before (outer to) @blueprint.route() instead of after it. In Flask, @route() must be the outermost decorator because it registers the function it receives. When the order is reversed, @route() registers the original undecorated function, and the auth wrapper is never in the call chain. This silently disables authentication on these routes. This vulnerability is fixed in 0.54.8.
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 confidenceIn the changedetection.io application, the @login_optionally_required decorator was placed as an outer decorator before @blueprint.route(). Since Flask's @route() must be the outermost decorator to properly register the decorated function, this incorrect ordering caused @route() to register the original undecorated function instead of the auth-wrapped version, silently disabling authentication on affected routes.
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< 0.54.8CVSS 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
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 the installed version of changedetection.ioCheck the version in your installation. Common methods: check the requirements.txt, setup.py, pyproject.toml, or run 'pip show changedetection' if installed via pip. The application may also display its version in the web UI footer.Affected if The version is lower than 0.54.8 (e.g., 0.54.7, 0.54.0, etc.)
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Locate source files containing the @login_optionally_required decoratorSearch the codebase for files using this decorator, typically with a command like 'grep -r "login_optionally_required"' in the application source directory.Affected if Any route handlers found using this decorator in versions below 0.54.8 may have authentication bypassed.
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Examine the decorator ordering in the route definitionsOpen the source files identified in the previous step and inspect the function definitions that use @login_optionally_required. Check if @blueprint.route() or @app.route() appears AFTER @login_optionally_required rather than BEFORE it.Affected if The decorator order shows @login_optionally_required placed as the outer decorator (appearing first) before @route(), which means authentication is bypassed.
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Verify authentication behavior on affected endpointsIf you have access to the running application, attempt to access routes suspected of being affected (such as settings, watch edit, or other authenticated areas) without providing credentials. Compare the behavior to what the documentation states should require authentication.Affected if The endpoint allows unauthenticated access when it should require authentication, confirming the decorator ordering bug is exploitable in your environment.
You are affected if your changedetection.io version is below 0.54.8 AND your application has routes using @login_optionally_required that were defined with the decorator placed before @route(), resulting in unauthenticated access to protected endpoints.
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 · scoped0.54.8
Upgrade to version 0.54.8 or later to receive the patch that corrects the decorator ordering.
0.54.8
- Upgrade changedetection to version 0.54.8 or later to resolve the decorator ordering vulnerability that silently disables authentication
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-35490 — 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-2026-35490 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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