CVE-2026-47203

2.9 LOW 0.5% exploit odds Fix listed Other Server

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 0.5% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-19 21:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-23 16:06 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.5% in the next 30 days (EPSS).
Severity: 2.9 LOW (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-06-19 21:16 UTC
Last modified: 2026-06-23 16:06 UTC
Exploit probability: 0.5% · EPSS, next 30 days
Weakness: CWE-178
Record status: Deferred

Attack profile CVSS 4.0 · 2.9

Attack vector: Network
Complexity: High
Attack requirements: Present
Privileges needed: None
User interaction: None
Confidentiality: Low
Integrity: None
Availability: None

Raw vector

CVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2026-47203.md and follow it. Check whether this project is affected by CVE-2026-47203. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record