Critical
changedetection.io has an Authentication Bypass via Decorator Ordering
Type: advisorySources: OSV
changedetection.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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-35490
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 05:15 UTC · Revision 1
Source evidence
changedetection.io has an Authentication Bypass via Decorator Ordering
core-osv · Original sourcePublished 7 Apr 2026, 14:55 UTC
changedetection.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.
osv:CVE-2026-35490
Complete source record
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"title": "changedetection.io has an Authentication Bypass via Decorator Ordering",
"summary": "changedetection.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.",
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"modified": "2026-10-28T02:30:33.136752989Z",
"provider": "osv",
"references": [
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"https://github.com/dgtlmoon/changedetection.io/security/advisories/GHSA-jmrh-xmgh-x9j4",
"https://nvd.nist.gov/vuln/detail/CVE-2026-35490"
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},
"source_id": "core-osv",
"document_id": 500462,
"published_at": "2026-04-07T14:55:24.12+00:00"
}