CVE-2026-82685 Confirmation token accepted on any record in AshAuthentication
An authenticated attacker can hijack another user's account by replaying their own email confirmation token against the victim's record.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-82685?
CVE-2026-82685 is a high-severity authentication bypass vulnerability in team-alembic ash_authentication, published on 17 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Authorization Bypass Through User-Controlled Key vulnerability in team-alembic AshAuthentication allows an authenticated attacker to overwrite and confirm another user's email address, and so take over that account. A confirmation token issued to one user is accepted on any other user's record.
AshAuthentication.AddOn.Confirmation.ConfirmChange verifies the token's signature and its act claim, then applies the changes stored against that token to whichever record the changeset targets, never comparing the sub claim against changeset.data. An attacker who registers an account and changes their own email replays the resulting token against a victim's record id, writing in their own address with force_change_attributes/2 and stamping confirmed_at, after which an ordinary password reset yields the account. The library's own confirmation flow is unaffected, because AshAuthentication.AddOn.Confirmation.Actions.confirm/3 resolves sub to a user and targets that record.
This issue affects ash_authentication: from 0.5.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.
Weakness: CWE-639
Which versions are affected by CVE-2026-82685?
1 open source package ship an affected version, including ash_authentication.
| Package | Affected | Fixed in |
|---|---|---|
ash_authentication Hex | From 0.5.0 | 4.15.0, 5.0.0-rc.14 |
How do I fix CVE-2026-82685?
Upgrade ash_authentication to a fixed version for your release line: 4.15.0 or 5.0.0-rc.14.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-82685 being exploited?
There is no known exploitation of CVE-2026-82685 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-82685, GHSA-g636-26vf-2w63.