Authelia is an open-source authentication and authorization server providing two-factor authentication and single sign-on (SSO) for applications via a web portal. In versions 4.38.0 through 4.39.19, when a user authenticates via Basic Auth (i.e via the Authorization header with the Basic scheme) on the authz verification endpoint, Authelia takes the username directly from the Authorization header and passes it as is to the regulation system for ban checking and attempt recording. LDAP treats usernames case insensitively : john, John, and JOHN all bind as the same user. But the regulation SQL queries treat the lookup of these values in certain scenarios as case sensitive. This allows each variation of a usernames case to have its own ban bucket. Upgrade to 4.39.20 to receive a patch. As a workaround, explicitly disable the basic auth mechanism.
CVE-2026-47203
This low-severity CVE scores 2.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 77% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 2.9
- EG Score
- 2.9(medium)
- EPSS
- 22.8%
- KEV
- Not listed
Published
May 29, 2026
Last Modified
June 23, 2026
References (2)
- security-advisories@githubhttps://github.com/authelia/authelia/commit/b8985b57b70acdff8f204ed426ff619e763461ad
- security-advisories@githubhttps://github.com/authelia/authelia/security/advisories/GHSA-hjj4-hfjm-fmrj
Vendor Advisories for CVE-2026-47203(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
Go(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| github.com/authelia/authelia/v4 | — | 4.39.20 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 34× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-14 17:01 UTCEG score recompute
- 2026-07-13 22:30 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 17:20 UTCEG score recompute
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-08 17:15 UTCEG score recompute
- 2026-07-08 15:16 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-02 21:23 UTCEG score recompute
- 2026-07-01 15:07 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-29 23:22 UTCEG score recompute
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
Show 14 moreShow fewer
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-27 01:23 UTCEG score recompute
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-24 14:05 UTCEPSS rescore
- 2026-06-24 02:46 UTCEG score recompute
- 2026-06-23 21:33 UTCEPSS rescore
- 2026-06-23 21:33 UTCEPSS rescore
- 2026-06-19 21:38 UTCEG score recompute▲ 2.90
- 2026-06-19 21:37 UTCNVD updateCVSS v3 → 2.9 · CVSS v4 → 2.9
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-13 12:05 UTCEG score recompute
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-05-29 22:26 UTCEG score recompute
Frequently asked(5)
What is CVE-2026-47203?
When was CVE-2026-47203 disclosed?
Is CVE-2026-47203 actively exploited?
What is the CVSS score of CVE-2026-47203?
How do I remediate CVE-2026-47203?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-47203
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