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TI-2026-57079 Aliases CVE-2026-82761

Magic link single-use tokens replayable via TOCTOU race in AshAuthentication

Priority MEDIUM 48CWE-367Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in team-alembic AshAuthentication allows an attacker holding a leaked magic link to replay its single-use token and authenticate as the target subject. A magic link configured with single_use_token?, which is the default, is meant to be redeemable exactly once, but nothing serialises the token's validity check against its consumption, so concurrent redemptions of one token all succeed and each yields a full user token. Sign-in verifies the JWT with Jwt.verify/4 and revokes it only afterwards: AshAuthentication.Strategy.MagicLink.SignInPreparation revokes in a Query.after_action callback, and AshAuthentication.Strategy.MagicLink.SignInChange in an after_transaction hook that runs once the sign-in has already committed. AshAuthentication.TokenResource.Actions.revoke/3 writes the revocation as an upsert, so a concurrent duplicate revocation silently succeeds instead of conflicting and no request ever loses the race. This issue affects ash_authentication: from 3.9.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0056 46th percentileScored 2026-11-07
Fix Fixed ash_authentication (team-alembic): 4.15.0, 5.0.0-rc.14

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
team-alembicash_authentication3.9.0 to before 4.15.0; 5.0.0-rc.0 to before 5.0.0-rc.144.15.0, 5.0.0-rc.14Patch availableCNA
  • ash_authentication Vendorteam-alembic Affected 3.9.0 to before 4.15.0; 5.0.0-rc.0 to before 5.0.0-rc.14 Fixed in 4.15.0, 5.0.0-rc.14 Patch available CNA

CPE names CNA · 1

CPEVersionsRoleVendor
cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*———
  • cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:* Versions — — ·—

Remediation

  • Fix · CNA ash_authentication (team-alembic) Fixed in 4.15.0, 5.0.0-rc.14

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    team-alembic ash_authentication 4.15.0, 5.0.0-rc.14

    14 records Highest priority Priority MEDIUM 5 MEDIUM, 9 LOW

    Other records, highest priority first

    • TI-2026-59214 Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication PhoenixPriority MEDIUM 49
    • TI-2026-58664 `require_confirmed_with` is not enforced on the action and fails open on an unreadable attribute in AshAuthenticationPriority MEDIUM 49
    • TI-2026-53751 Remember-me sign-in guard reads a session key that is never written in ash_authentication, allowing session replacementPriority MEDIUM 49
    Show all 14 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-82761

References

Patch 2

Advisory 1

Other 3

  • TI-2026-36668 OAuth2/OIDC account takeover in AshAuthentication via email-based user matching CVSS 4.0CRITICAL 9.2
  • TI-2026-46782 Purpose-limited JWT accepted as full bearer authentication in AshAuthentication CVSS 4.0HIGH 7.6
  • TI-2026-59214 Revoked session accepted because the session jti is never checked in AshAuthentication and AshAuthentication Phoenix CVSS 4.0CRITICAL 9.1
  • TI-2026-58664 `require_confirmed_with` is not enforced on the action and fails open on an unreadable attribute in AshAuthentication CVSS 4.0CRITICAL 9.1
  • TI-2026-53751 Remember-me sign-in guard reads a session key that is never written in ash_authentication, allowing session replacement CVSS 4.0CRITICAL 9.1
  • TI-2026-47468 Reflected XSS in AshAuthentication confirmation and magic link interaction forms CVSS 4.0LOW 2.1
See all 23 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences