CVE-2026-82760: Team-Alembic Ash Authentication

High severity, CVSS 8.2. EPSS: 0.7% chance of exploitation in the next 30 days.

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.

Affected products

• Team-Alembic Ash Authentication: from 4.8.0, before 4.15.0 (fixed in 4.15.0); from 5.0.0-rc.0, before 5.0.0-rc.14 (fixed in 5.0.0-rc.14)

Published 2026-09-17. Last modified 2026-09-18.