CVE-2026-119446: Session fixation in the CLI login flow allows an unauthenticated attacker to obtain a user's API token

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 10 Nov 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.5%

EPSS score, percentile 41 of all scored records. A probability estimated by FIRST, not a report of exploitation.

CISA's SSVC assessment in the CVE record lists exploitation as poc.

How severe?

9.4 Critical

CVSS v4.0 base score, given by the CNA

What should I do?

Upgrading does not revoke tokens already handed out. Full textSolution from the CVE record.

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (2)

Which versions are affected?

Affected

• from 2.5.0 to before 2.5.3
• from 2.5.0 to before 2.5.3

Versions by product

Source: CISA KEV 2026.11.10, as of 10 Nov 2026; FIRST EPSS, as of 12 Nov 2026; CVE List, as of 13 Nov 2026. About the data.

Description

Session fixation in the CLI login flow allows an unauthenticated attacker to obtain a user's API token

Session Fixation vulnerability in the CLI login flow in nerves-hub nerves_hub_web allows an unauthenticated attacker to obtain an API token for another user's account via a crafted login link. Starting a CLI login with POST /api/auth/cli_session needs no authentication and returns a polling token, a confirmation URL that carries that token, and a confirmation code. When a signed-in user opens that URL and clicks Confirm, NervesHub.Accounts.verify_cli_session_token/2 creates an API token for the user's account and stores it on the login, and the next poll of GET /api/auth/cli_session/<token> returns it to whoever started the login. The confirmation code is only displayed and is never compared with anything, so it cannot show that the person confirming is the one who started the login. The confirm form carries a CSRF token and the page cannot be framed, so the attacker has to persuade the user to open the link and click the button themselves. This issue affects nerves_hub: from 2.5.0 before 2.5.3.

Source: CVE List, as of 13 Nov 2026. About the data.

What to do

Advisories and patches

• Fix commit 3131f17 in nerves-hub/nerves_hub_web (Patch)
• CLI login links give an API token to whoever sent them (Vendor advisory)

Solution (from the CVE record)

Upgrading does not revoke tokens already handed out. A token from a CLI login is an ordinary API token with a note the client chose, so one an attacker obtained looks like any other. After upgrading, users should review their API tokens on the account page and delete any they do not recognise.

Workaround (from the CVE record)

Block POST /api/auth/cli_session at the reverse proxy until the upgrade. It is the only entry point that creates a CLI login, so no link can be produced while it is blocked. CLIs can still sign in with an email and password (nh user auth, POST /api/users/auth), or use an API token created on the account page.

This summary is based on the CVE record as of 13 Nov 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Source: CVE List, as of 13 Nov 2026. About the data.

Timeline