CVE-2026-33525: Authelia is an open-source authentication and authorization server providing two-factor authentication and sin

Routine

MEDIUM 6.1DOWNGRADE

CVE-2026-33525 is a medium-severity flaw (CVSS 6.1) affecting authelia. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 `script-src` and `connect-src` directives have been modified it's almost impossible for this to have a meaningful impac

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-03-26
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: authelia

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-26 20:16 UTCPublished CVE record published
2026-06-17 10:37 UTCUpdated Record last modified

authelia authelia DOWNGRADE

Affected: 4.39.15

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.39.15

1. Check installed version

apt-cache policy authelia || rpm -q authelia || authelia --version

2. No fixed release: DOWNGRADE to a release before 4.39.15 (Debian / Ubuntu)

apt-cache madison authelia sudo apt install authelia=<VERSION_BEFORE_4.39.15> sudo apt-mark hold authelia

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list authelia sudo dnf downgrade authelia-<VERSION_BEFORE_4.39.15> sudo dnf versionlock add authelia

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-33525?

authelia: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-33525 being exploited?

CVE-2026-33525 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-33525 affect?

CVE-2026-33525 affects authelia. Severity is medium (CVSS 6.1). 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

How urgent is CVE-2026-33525?

Priority 30/100. Public exploit reference

References

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