CVE-2020-1744Network attack vector

Brute-force protection bypass via missed OTP events

Published Mar 24, 2020 · Updated Aug 4, 2024

Improper handling of failed OTP events in Red Hat build of Keycloak before 9.0.1 allows remote attackers to bypass brute-force protections. The Conditional OTP post-login flow fails to enqueue unsuccessful OTP login events for BruteForceProtector, so its failure counters and lockout logic are not applied. The attack requires an identity provider configured with that post-login flow; repeated invalid OTP attempts can continue without the intended brute-force throttling or lockout.

CVSS severity5.6
Medium
EPSS probability1.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper handling of failed OTP events in Red Hat build of Keycloak before 9.0.1 allows remote attackers to bypass brute-force protections. The Conditional OTP post-login flow fails to enqueue unsuccessful OTP login events for BruteForceProtector, so its failure counters and lockout logic are not applied. The attack requires an identity provider configured with that post-login flow; repeated invalid OTP attempts can continue without the intended brute-force throttling or lockout.

The record

CVE
CVE-2020-1744
Published
Mar 24, 2020
Updated
Aug 4, 2024
Vendor
Red Hat
Product
Red Hat build of Keycloak
Classifications
CWE-755, T1110
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 24, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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.

  1. Affected versionversion=all keycloak versions prior to 9.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Red Hat build of Keycloakversion=all keycloak versions prior to 9.0.1

Published CVSS scores

5.6Red Hat, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-755Improper Handling of Exceptional Conditions
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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