Account takeover via OAuth redirect authority injection
Published Feb 21, 2026 · Updated Feb 21, 2026
Open redirect in FeathersJS Feathers before 5.0.40 allows remote attackers to steal OAuth access tokens through a crafted callback redirect. The OAuth strategy concatenates the configured base origin with the unvalidated redirect query value, so an @ authority delimiter sends the fragment token to an attacker-controlled host. When the origins array contains an entry lacking a trailing slash, victim interaction with the OAuth flow exposes the token and enables account impersonation.
Summary
What happened
Open redirect in FeathersJS Feathers before 5.0.40 allows remote attackers to steal OAuth access tokens through a crafted callback redirect. The OAuth strategy concatenates the configured base origin with the unvalidated redirect query value, so an @ authority delimiter sends the fragment token to an attacker-controlled host. When the origins array contains an entry lacking a trailing slash, victim interaction with the OAuth flow exposes the token and enables account impersonation.
The record
- CVE
- CVE-2026-27191
- Published
- Feb 21, 2026
- Updated
- Feb 21, 2026
- Vendor
- FeathersJS
- Product
- Feathers
- Classifications
- CWE-601, T1528
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 21, 2026CVE publishedPublication date reported by the CVE source.
- Feb 21, 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?
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- Affected versionversion=< 5.0.40
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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