Answer in brief
CVE-2021-43177 records a Medium severity (CVSS 5.3) vulnerability in Improper one time password handling in devise-two-factor. The current sources do not mark it as known exploited. The current feed maps devise-two-factor (rubygems). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps devise-two-factor (rubygems). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| devise-two-factorrubygems | >=0 <4.0.2 | 4.0.2 |
Published upstream
Apr 7, 2022
Evidence: source:osv:source_dates:source-dates:recordSource modified
Aug 27, 2026
Evidence: source:osv:source_dates:source-dates:recordFirst seen by HOL
Aug 7, 2026
### Impact As a result of an incomplete fix for CVE-2015-7225, in versions of devise-two-factor prior to 4.0.2 it is possible to reuse a One-Time-Password (OTP) for one (and only one) immediately trailing interval. ### Patches This vulnerability has been patched in version 4.0.2 which was released on March 24th, 2022. Individuals using this package are strongly encouraged to upgrade as soon as possible. ### Credit for discovery Benoit Côté-Jodoin Michael Nipper - https://github.com/tinfoil/devise-two-factor/issues/106
Quoted source text, attributed separately from HOL analysis.