Vulnerability · Published Sep 17, 2026 · Assigned by EEF
CVE-2026-82760Superlinear base62 decoding exhausts CPU and memory in AshAuthentication API key sign-in
High 8.2
In plain English
A high-severity security flaw in ash_authentication from team-alembic. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 55% of all known vulnerabilities).
Official 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 (as reported)
| Vendor | Product | Versions |
|---|---|---|
| team-alembic | ash_authentication | 4.8.0 – before 4.15.05.0.0-rc.0 – before 5.0.0-rc.14 |
| team-alembic | ash_authentication | f3a53f480088419788d5c3934af3131fa9066773 – before * |
Weakness: CWE-407 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
References
- https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-q876-xr24-2mcx related, vendor-advisory
- EEF CNA record for CVE-2026-82760 related
- OSV record EEF-CVE-2026-82760 related
- Introducing commit f3a53f4 in team-alembic/ash_authentication related
- Fix commit d5a5d4c in team-alembic/ash_authentication patch
- Fix commit dfb19c8 in team-alembic/ash_authentication patch