TOTP bypass via rolled-back account lockout
Published Apr 10, 2026 · Updated Apr 10, 2026
Improper TOTP attempt restriction in Vikunja before 2.3.0 allows remote attackers with a user's password to brute-force TOTP codes. The login handler rolls back the database session after HandleFailedTOTPAuth writes StatusAccountLocked, undoing every lockout while the in-memory failure counter continues rising. Exploitation requires a valid account password and TOTP-enabled local authentication; per-IP rate limiting slows a single source, but distributed attempts can exhaust the six-digit code space.
Summary
What happened
Improper TOTP attempt restriction in Vikunja before 2.3.0 allows remote attackers with a user's password to brute-force TOTP codes. The login handler rolls back the database session after HandleFailedTOTPAuth writes StatusAccountLocked, undoing every lockout while the in-memory failure counter continues rising. Exploitation requires a valid account password and TOTP-enabled local authentication; per-IP rate limiting slows a single source, but distributed attempts can exhaust the six-digit code space.
The record
- CVE
- CVE-2026-35597
- Published
- Apr 10, 2026
- Updated
- Apr 10, 2026
- Vendor
- Vikunja
- Product
- Vikunja
- Classifications
- CWE-307, T1110
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 10, 2026CVE publishedPublication date reported by the CVE source.
- Apr 10, 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=< 2.3.0
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
- Upstream TOTP lockout proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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