CVE-2026-42849: authentik is an open-source identity provider

This month

CRITICAL 9.3UPGRADE

CVE-2026-42849 is a critical-severity flaw (CVSS 9.3) affecting authentik. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

authentik is an open-source identity provider. Prior to versions 2025.12.5 and 2026.2.3, due to the implementation of stages in the SFE (Simple Flow Executor) in order to make the interface more compatible with legacy browsers, it was possible to use an XSS exploit in the AutosubmitStage. This issue has been patched in versions 2025.12.5 and 2026.2.3.

Why this priority

Critical severity

A fixed release or distro patch exists.

Risk facts

CVSS score	9.3 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-06-02
Last modified	2026-07-22

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

Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-02 21:16 UTCPublished CVE record published
2026-07-22 19:10 UTCUpdated Record last modified

goauthentik authentik UPGRADE

Affected: < 2025.12.5 · >= 2026.2.0 and < 2026.2.3

Fixed in: 2025.12.5, 2026.2.3

Safe to downgrade to: a release before 2026.2.0

1. Check installed version

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

2. UPGRADE to 2025.12.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade authentik

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade authentik

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2026.2.0 (Debian / Ubuntu)

apt-cache madison authentik sudo apt install authentik=<VERSION_BEFORE_2026.2.0> sudo apt-mark hold authentik

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list authentik sudo dnf downgrade authentik-<VERSION_BEFORE_2026.2.0> sudo dnf versionlock add authentik

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-2026-42849?

authentik: upgrade to 2025.12.5, 2026.2.3. Exact commands for each OS are on this page.

Is CVE-2026-42849 being exploited?

CVE-2026-42849 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-2026-42849 affect?

CVE-2026-42849 affects authentik. Severity is critical (CVSS 9.3). authentik is an open-source identity provider. Prior to versions 2025.12.5 and 2026.2.3, due to the implementation of stages in the SFE (Simple Flow Executor) in order to make the interface more compatible with legacy browsers, it was possi

How urgent is CVE-2026-42849?

Priority 40/100. Critical severity

Related CVEs

CVE-2026-49448 CRITICAL 9.8 UPGRADE authentik is an open-source identity provider
CVE-2026-49443 HIGH 8.8 UPGRADE authentik is an open-source identity provider
CVE-2026-41577 HIGH 7.5 UPGRADE authentik is an open-source identity provider
CVE-2026-47201 HIGH 8.5 UPGRADE authentik is an open-source identity provider
CVE-2026-41569 MEDIUM 6.1 UPGRADE authentik is an open-source identity provider

References

← Back to latest CVEs