CVE-2026-47203Network attack vector

Brute-force throttling bypass via case-variant usernames

Published Jun 19, 2026 · Updated Jun 19, 2026

Authentication throttling bypass in Authelia 4.38.0 through 4.39.19 allows remote attackers to extend password guessing via Basic Auth. The authz verification handler passes the Basic Authorization username unchanged to regulation SQL queries, so LDAP-equivalent case variants create separate ban buckets. Exposure requires Basic Auth, LDAP, username regulation, and a case-sensitive database; a guessed valid password grants access to protected data.

CVSS severity6.3
Medium
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication throttling bypass in Authelia 4.38.0 through 4.39.19 allows remote attackers to extend password guessing via Basic Auth. The authz verification handler passes the Basic Authorization username unchanged to regulation SQL queries, so LDAP-equivalent case variants create separate ban buckets. Exposure requires Basic Auth, LDAP, username regulation, and a case-sensitive database; a guessed valid password grants access to protected data.

The record

CVE
CVE-2026-47203
Published
Jun 19, 2026
Updated
Jun 19, 2026
Vendor
Authelia
Product
Authelia
Classifications
CWE-307, CWE-178, T1110.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 19, 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.

  1. Affected versionversion=>= 4.38.0, < 4.39.20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Authelia · Autheliaversion=>= 4.38.0, < 4.39.20

Published CVSS scores

6.3Authelia GitHub Security AdvisoryCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
2.9Authelia GitHub Security AdvisoryCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-307Improper Restriction of Excessive Authentication Attempts
CWE-178Improper Handling of Case Sensitivity
T1110.001Password Guessing

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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