Sign-in token minted for one resource accepted by another in AshAuthentication
Summary
| CVE | CVE-2026-80218 |
|---|---|
| State | PUBLISHED |
| Assigner | EEF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-17 14:17:30 UTC |
| Updated | 2026-09-18 18:16:18 UTC |
| Description | 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. |
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: 0.004540000 probability, percentile 0.387310000 (date 2026-09-20)
Problem Types: CWE-287 | CWE-287 CWE-287 Improper Authentication
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | Secondary | 7.6 | HIGH | 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/C... |
| 4.0 | CNA | CVSS | 7.6 | HIGH | 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 |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
LowUser Interaction
NoneConfidentiality
HighIntegrity
HighAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Team-alembic | Ash Authentication | affected 3.10.5 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 eca8cadea0f1595ed2c10a0c177b1da9aa9e5269 * git | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/team-alembic/ash_authentication/security/advisories/GHSA-3pr8... | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| github.com/team-alembic/ash_authentication/commit/eca8cadea0f1595ed2c10a... | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| cna.erlef.org/cves/CVE-2026-80218.html | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | cna.erlef.org | |
| github.com/team-alembic/ash_authentication/commit/7baac243ca651eee127a84... | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| github.com/team-alembic/ash_authentication/commit/2640e1872e1fef4e4606e6... | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| osv.dev/vulnerability/EEF-CVE-2026-80218 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | osv.dev | |
| 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: Jonatan Männchen / EEF (en)
CNA: James Harton (en)
There are currently no legacy QID mappings associated with this CVE.