Username enumeration via skipped fake password hash
Published Mar 3, 2025 · Updated Mar 3, 2025
Observable response discrepancy in Flask-AppBuilder before 4.5.3 allows remote attackers to enumerate usernames through login timing. The database-authentication login path skips an equivalent fake password-hash check for an unknown user, so Werkzeug 3.0.0 and later makes nonexistent-user responses measurably faster. The endpoint requires no authentication, but the oracle requires repeated measurements; it discloses account existence without exposing passwords or granting access.
Summary
What happened
Observable response discrepancy in Flask-AppBuilder before 4.5.3 allows remote attackers to enumerate usernames through login timing. The database-authentication login path skips an equivalent fake password-hash check for an unknown user, so Werkzeug 3.0.0 and later makes nonexistent-user responses measurably faster. The endpoint requires no authentication, but the oracle requires repeated measurements; it discloses account existence without exposing passwords or granting access.
The record
- CVE
- CVE-2025-24023
- Published
- Mar 3, 2025
- Updated
- Mar 3, 2025
- Vendor
- dpgaspar
- Product
- Flask-AppBuilder
- Classifications
- CWE-204, T1589.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 3, 2025CVE publishedPublication date reported by the CVE source.
- Mar 3, 2025Record 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=< 4.5.3
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
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Technologies
Your stack
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Your stack
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