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Vulnerabilities

Vulnerability · CVE-2026-33525

Authelia is an open-source authentication and authorization server providing two-factor authentication and single sign-on (SSO) for applications via a web portal.

Published Mar 26, 2026 · catalog updated Jun 17, 2026 · Authelia is an open-source

Check if you run it

No confirmed exploitation is on record for CVE-2026-33525. EPSS is 0.32%. Act only if a listed version of Authelia is an open-source is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Authelia is an open-source).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low0.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.32%
Remediation
Advisory link
Affected products
cpe authelia/authelia

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 version 4.39.15, an attacker may potentially be able to inject javascript into the Authelia login page if several conditions are met simultaneously. Unless both the and directives have been modified it's almost impossible for this to have a meaningful impact. However if both of these are and they are done so without consideration to their potential impact; there is a are situations where this vulnerability could be exploited. This is caused to the lack of neutralization of the cookie value when rendering the HTML template. This vulnerability is likely difficult to discover though fingerprinting due to the way Authelia is designed but it should not be considered impossible. The additional requirement to identify the secondary application is however likely to be significantly harder to identify along side this, but also likely easier to fingerprint. Users should upgrade to 4.39.16 or downgrade to 4.39.14 to mitigate the issue. The overwhelming majority of installations will not be affected and no workarounds are necessary. The default value for the Content Security Policy makes exploiting this weakness completely impossible. It's only possible via the deliberate removal of the Content Security Policy or deliberate inclusion of clearly noted unsafe policies.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe authelia/authelia4.39.15

How to fix CVE-2026-33525

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-33525. EPSS is 0.32%. Act only if a listed version of Authelia is an open-source is installed.

Which versions are affected?

Compare what you have installed with 4.39.15. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.32%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 26, 2026 · NIST NVD

    Detected

    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 version 4.39.15, an attacker may potentially be able to inject javascript into the Authelia login page if several conditions are met simultaneously. Unless both the and directives have been modified it's almost impossible for this to

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 version 4.39.15, an attacker may potentially be able to inject javascript into the Authelia login page if several conditions are met simultaneously. Unless both the and directives have been modified it's almost impossible for this to

Sources

  • CVE.orgVulnerability recordCVE-2026-33525

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-33525

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-33525

    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 version 4.39.15, an attacker may potentially be able to inject javascript into the Authelia login page if several

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.