eef-cve-2026-82685
CVSS 7.6 osv_hex
Description
## Summary 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.
Timeline
- Published
- unknown
- Last Modified
- unknown
CVSS Details
CVSS details not available.
Affected Products
No product information available.
Weaknesses (CWE)
References
- https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-g636-26vf-2w63
- https://cna.erlef.org/cves/CVE-2026-82685.html
- https://github.com/team-alembic/ash_authentication/commit/1d4bb00617aecae85c33f2ff5bc7e094c6449a6e
- https://github.com/team-alembic/ash_authentication/commit/d7c15c21d39c009206e010cd67e2d86370fe7a28
- https://github.com/team-alembic/ash_authentication/commit/2a2396af131ab67e2f445b805fecce8e6ca86c0e
- https://hex.pm/packages/ash_authentication
Linked Vulnerabilities
No linked vulnerabilities found.
{
"affected": [
{
"database_specific": {
"source": "https://cna.erlef.org/osv/EEF-CVE-2026-82685.json"
},
"package": {
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"purl": "pkg:hex/ash_authentication"
},
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{
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"ranges": [
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"events": [
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"repo": "https://github.com/team-alembic/ash_authentication",
"type": "GIT"
}
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],
"aliases": [
"CVE-2026-82685",
"GHSA-g636-26vf-2w63"
],
"credits": [
{
"name": "Peter Ullrich",
"type": "REPORTER"
},
{
"name": "James Harton",
"type": "REMEDIATION_DEVELOPER"
},
{
"name": "Jonatan Männchen / EEF",
"type": "ANALYST"
}
],
"database_specific": {
"capec_ids": [
"CAPEC-21"
],
"cpe_ids": [
"cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
],
"cwe_ids": [
"CWE-639"
]
},
"details": "## Summary\n\nAuthorization 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.\n\n`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.\n\nThis 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.",
"id": "EEF-CVE-2026-82685",
"modified": "2026-09-17T13:26:04.340611555Z",
"published": "2026-09-17T13:08:56.491Z",
"references": [
{
"type": "ADVISORY",
"url": "https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-g636-26vf-2w63"
},
{
"type": "WEB",
"url": "https://cna.erlef.org/cves/CVE-2026-82685.html"
},
{
"type": "WEB",
"url": "https://github.com/team-alembic/ash_authentication/commit/1d4bb00617aecae85c33f2ff5bc7e094c6449a6e"
},
{
"type": "FIX",
"url": "https://github.com/team-alembic/ash_authentication/commit/d7c15c21d39c009206e010cd67e2d86370fe7a28"
},
{
"type": "FIX",
"url": "https://github.com/team-alembic/ash_authentication/commit/2a2396af131ab67e2f445b805fecce8e6ca86c0e"
},
{
"type": "PACKAGE",
"url": "https://hex.pm/packages/ash_authentication"
}
],
"schema_version": "1.9.0",
"severity": [
{
"score": "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",
"type": "CVSS_V4"
}
],
"summary": "Confirmation token accepted on any record in AshAuthentication"
}