Vulnerability · Published Sep 17, 2026 · Assigned by EEF
CVE-2026-82685Confirmation token accepted on any record in AshAuthentication
High 7.6
In plain English
A high-severity authorization bypass via user-controlled key in ash_authentication from team-alembic. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| team-alembic | ash_authentication | 0.5.0 – before 4.15.05.0.0-rc.0 – before 5.0.0-rc.14 |
| team-alembic | ash_authentication | 1d4bb00617aecae85c33f2ff5bc7e094c6449a6e – before * |
Weakness: CWE-639 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-g636-26vf-2w63 related, vendor-advisory
- EEF CNA record for CVE-2026-82685 related
- OSV record EEF-CVE-2026-82685 related
- Introducing commit 1d4bb00 in team-alembic/ash_authentication related
- Fix commit d7c15c2 in team-alembic/ash_authentication patch
- Fix commit 2a2396a in team-alembic/ash_authentication patch