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TI-2026-57078 Aliases CVE-2026-82760

Superlinear base62 decoding exhausts CPU and memory in AshAuthentication API key sign-in

Priority LOW 37CWE-407Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-407.

Summary

Inefficient Algorithmic Complexity vulnerability in team-alembic AshAuthentication allows an unauthenticated attacker to exhaust CPU and memory via an oversized base62 segment in a submitted API key. AshAuthentication.Base.decode62/1 in lib/ash_authentication/base.ex splits its argument into one binary per character and folds it with charval62/2, which recomputes Integer.pow(62, index) at every position instead of accumulating by Horner's method, so cost grows roughly cubically in the input length. bindecode62/1 in the same module is quadratic through Integer.undigits/2 and Integer.digits/2. Neither function caps byte_size/1, and AshAuthentication.Strategy.ApiKey.SignInPreparation passes the underscore-separated segments of the submitted key straight into both, before any key lookup and without prior authentication. The surrounding rescue clauses catch exceptions, not CPU or memory exhaustion. This issue affects ash_authentication: from 4.8.0 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 0.00737 54th 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
No
Technical impact
Partial

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_authentication4.8.0 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 4.8.0 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-2026-82760

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-2026-57079 Magic link single-use tokens replayable via TOCTOU race in AshAuthentication CVSS 4.0CRITICAL 9.1
See all 23 →

Sources

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