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.
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Solution
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Workaround
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Thu, 17 Sep 2026 19:30:00 +0000
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ssvc
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Thu, 17 Sep 2026 13:30:00 +0000
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| 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. | |
| Title | Superlinear base62 decoding exhausts CPU and memory in AshAuthentication API key sign-in | |
| First Time appeared |
Team-alembic
Team-alembic ash Authentication |
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| Weaknesses | CWE-407 | |
| CPEs | cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Team-alembic
Team-alembic ash Authentication |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-09-17T18:21:26.238Z
Reserved: 2026-08-31T01:00:10.817Z
Link: CVE-2026-82760
Updated: 2026-09-17T18:21:18.679Z
Status : Received
Published: 2026-09-17T14:17:33.237
Modified: 2026-09-17T19:17:04.490
Link: CVE-2026-82760
No data.
OpenCVE Enrichment
No data.