Confirmation token accepted on any record in AshAuthentication

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-82685
StatePUBLISHED
AssignerEEF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 14:17:32 UTC
Updated2026-09-18 18:16:18 UTC
DescriptionAuthorization 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.

Risk And Classification

Primary CVSS: v4.0 7.6 HIGH from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.004740000 probability, percentile 0.401310000 (date 2026-09-20)

Problem Types: CWE-639 | CWE-639 CWE-639 Authorization Bypass Through User-Controlled Key

VersionSourceTypeScoreSeverityVector
4.06b3ad84c-e1a6-4bf7-a703-f496b71e49dbSecondary7.6HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS7.6HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Team-alembic Ash Authentication affected 0.5.0 4.15.0 semver Not specified
CNA Team-alembic Ash Authentication affected 5.0.0-rc.0 5.0.0-rc.14 semver Not specified
CNA Team-alembic Ash Authentication affected 1d4bb00617aecae85c33f2ff5bc7e094c6449a6e * git Not specified

References

ReferenceSourceLinkTags
github.com/team-alembic/ash_authentication/commit/2a2396af131ab67e2f445b... 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
github.com/team-alembic/ash_authentication/security/advisories/GHSA-g636... 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
osv.dev/vulnerability/EEF-CVE-2026-82685 6b3ad84c-e1a6-4bf7-a703-f496b71e49db osv.dev
github.com/team-alembic/ash_authentication/commit/d7c15c21d39c009206e010... 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
cna.erlef.org/cves/CVE-2026-82685.html 6b3ad84c-e1a6-4bf7-a703-f496b71e49db cna.erlef.org
github.com/team-alembic/ash_authentication/commit/1d4bb00617aecae85c33f2... 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Peter Ullrich (en)

CNA: James Harton (en)

CNA: Jonatan Männchen / EEF (en)

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