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CVE-2019-5421

30
FAUCET Score

CVE-2019-5421 is a critical vulnerability affecting Plataformatec Devise versions 4.5.0 and earlier, specifically within the lockable module's #increment_failed_attempts method. This flaw (CWE-367) allows multiple concurrent login attempts to bypass the account lockout mechanism, making brute-force attacks highly effective. With a CVSS score of 9.8 (CRITICAL), it is easily exploitable over the network with low complexity, potentially leading to full compromise of confidentiality, integrity, and availability. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
<= 4.5.0CPE matchmatch criteria
cpe:2.3:a:plataformatec:devise:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.56%
Probability of exploitation in next 30 days
EPSS Percentile
72.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0156 is in the 60th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
rubygemspatch availablevia ghsa
Product: deviseFixed in: 4.6.0

Vendor Advisories (1)

rubygemsGHSA-73rf-6mrf-759qmedium

devise Time-of-check Time-of-use Race Condition vulnerability

Mar 19, 2019

References

github.com / plataformatec/devise/issues/4981
ExploitIssue TrackingThird Party Advisory
github.com / plataformatec/devise/pull/4996
PatchThird Party Advisory