Authenticated collection tampering via broken ownership checks
Published Feb 27, 2026 · Updated Feb 27, 2026
Incorrect authorization in ClipBucket V5 before 5.5.3 - #59 allows remote authenticated users to add or remove another user’s collection items. The add_to_collection.php endpoint inserts supplied collection and object identifiers without checking ownership, while removeItemFromCollection() mis-evaluates ownership because negation binds before equality. Any normal account can alter victim collections, including collections configured to disallow public additions, but the flaw does not grant administrative control.
Summary
What happened
Incorrect authorization in ClipBucket V5 before 5.5.3 - #59 allows remote authenticated users to add or remove another user’s collection items. The add_to_collection.php endpoint inserts supplied collection and object identifiers without checking ownership, while removeItemFromCollection() mis-evaluates ownership because negation binds before equality. Any normal account can alter victim collections, including collections configured to disallow public additions, but the flaw does not grant administrative control.
The record
- CVE
- CVE-2026-28354
- Published
- Feb 27, 2026
- Updated
- Feb 27, 2026
- Vendor
- MacWarrior
- Product
- ClipBucket V5
- Classifications
- CWE-639, CWE-863, T1565.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 27, 2026CVE publishedPublication date reported by the CVE source.
- Feb 27, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 5.5.3 - #59
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Vendor advisory HTTP reproductionproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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