Insufficient Session Expiration vulnerability in team-alembic AshAuthentication allows an attacker who obtains a victim's OAuth2 state value to replay the callback and sign that victim into an attacker-controlled account.
AshAuthentication.Strategy.OAuth2.Plug.callback/2 clears the stored session_params through a rebinding step inside its with chain, conn <- delete_session(conn, session_key). Elixir evaluates the else block in the scope enclosing the with, so every failure path (the provider returning ?error=access_denied, an invalid code, a token-exchange error, or a registration or sign-in failure) reaches store_authentication_result/2 holding the original connection and the session entry is never removed. The value the module's own comment describes as protection against a CSRF-related attack is therefore consumed only when authentication succeeds, and survives a cancelled or failed attempt until the next request phase or session expiry.
This issue affects ash_authentication: from 0.6.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.
{
"cna_assigner": "EEF",
"cwe_ids": [
"CWE-613"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81637.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "c5f589058e04239263f50a1430eb17ea6d5dd1a2"
},
{
"fixed": "bd4352303bc9d72d007f6818775267585a4bcc2f"
}
],
"source": "AFFECTED_FIELD",
"strategy": "ChangesAt"
},
{
"range": [
{
"introduced": "0.6.0"
},
{
"fixed": "4.15.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"introduced": "5.0.0-rc.0"
},
{
"fixed": "5.0.0-rc.14"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"fixed": "c5f589058e04239263f50a1430eb17ea6d5dd1a2"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "bd4352303bc9d72d007f6818775267585a4bcc2f"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "d7f939cd02bd618bcaa304631846fa75ffc419d7"
}
],
"source": "REFERENCES_COMMIT"
}
]
}