Improper Authentication vulnerability in team-alembic AshAuthentication allows an attacker holding a sign-in token for one authenticated resource to be signed in as a user of a different resource.
AshAuthentication.Strategy.Password.SignInWithTokenPreparation.extract_primary_keys_from_subject/2 parses the JWT sub claim (for example user?id=1) with URI.parse/1 and keeps only its query string, discarding the path segment that names the subject the token was issued for. Nothing else restores that binding: AshAuthentication.Jwt.verify/3 checks the signature, exp, nbf, jti and the library-version claims, the purpose check only requires sign_in, and the remaining comparison is over primary-key field names, which are identical across resources. The WebAuthn sign-in and remember-me preparations carry copies of the same helper and drop the path in the same way. The magic link sign-in path pins the subject name against the resource and is not affected.
This issue affects ash_authentication: from 3.10.5 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.
{
"cna_assigner": "EEF",
"cwe_ids": [
"CWE-287"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80218.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "eca8cadea0f1595ed2c10a0c177b1da9aa9e5269"
},
{
"fixed": "2640e1872e1fef4e4606e601bf00102cff784c03"
}
],
"source": "AFFECTED_FIELD",
"strategy": "ChangesAt"
},
{
"range": [
{
"introduced": "3.10.5"
},
{
"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": "eca8cadea0f1595ed2c10a0c177b1da9aa9e5269"
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],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "2640e1872e1fef4e4606e601bf00102cff784c03"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
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"source": "REFERENCES_COMMIT"
}
]
}