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CVE PROGRAM SOURCE RECORD8.2 High

CVE-2026-82760

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

Description

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

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

team-alembic ash_authentication

Default version status: unaffected

  • 4.8.0 to < 4.15.0affected
  • 5.0.0-rc.0 to < 5.0.0-rc.14affected
pkg:hex/ash_authentication

team-alembic ash_authentication

Default version status: unaffected

  • f3a53f480088419788d5c3934af3131fa9066773 to < *affected
pkg:github/team-alembic/ash_authentication

References