CVE-2019-5421

Exp

Plataformatec Devise version 4.5.0 and earlier, using the lockable module contains a CWE-367 vulnerability in The `Devise::Models::Lockable` class, more specifically at the `#increment_failed_attempts` method. File location: lib/devise/models/lockable.rb that can result in Multiple concurrent requests can prevent an attacker from being blocked on brute force attacks. This attack appear to be exploitable via Network connectivity - brute force attacks. This vulnerability appears to have been fixed in 4.6.0 and later.

Published: 2019-04-03 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-5421 is rated High Exploit Risk (70/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.23%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2019-5421

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2019-5421

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 0.26% 0.23% -0.03%
2 2026-03-01 0.23% 0.26% +0.03%
3 2026-02-04 — 0.23% —

Full EPSS history (41 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-5421

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2019-5421

GitHub Security Advisory for CVE-2019-5421

GHSA-73rf-6mrf-759q · Severity: medium · Ecosystem: rubygems — devise Time-of-check Time-of-use Race Condition vulnerability

OS Trackers for CVE-2019-5421

vendor priority summary link
debian not yet assigned CVE-2019-5421 not yet assigned priority: Debian including 1 source packages (ruby-devise), 2 status rows across 2 suites (bookworm, bullseye): resolved 2. https://security-tracker.debian.org/tracker/CVE-2019-5421
ubuntu low CVE-2019-5421 low priority: Ubuntu including 2 source packages (gitlab, ruby-devise), 38 status rows across 19 suites (bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 19, released 12, ignored 3, needs-triage 2, needed 1, not-affected 1. https://ubuntu.com/security/CVE-2019-5421

Affected software / configurations for CVE-2019-5421

Vendor Product Version Raw CPE
plataformatec devise <= 4.5.0 cpe:2.3:a:plataformatec:devise:*:*:*:*:*:*:*:*

References for CVE-2019-5421

URL Tags
https://github.com/plataformatec/devise/issues/4981 Exploit Issue Tracking Third Party Advisory
https://github.com/plataformatec/devise/pull/4996 Patch Third Party Advisory
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