Superlinear base62 decoding exhausts CPU and memory in AshAuthentication API key sign-in
Summary
| CVE | CVE-2026-82760 |
|---|---|
| State | PUBLISHED |
| Assigner | EEF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-17 14:17:33 UTC |
| Updated | 2026-09-17 19:17:04 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 8.2 HIGH from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-407 | CWE-407 CWE-407 Inefficient Algorithmic Complexity
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | Secondary | 8.2 | HIGH | 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/E:X/C... |
| 4.0 | CNA | CVSS | 8.2 | HIGH | 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 |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
NoneUser Interaction
NoneConfidentiality
NoneIntegrity
NoneAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Team-alembic | Ash Authentication | affected 4.8.0 4.15.0 semver | Not specified |
| CNA | Team-alembic | Ash Authentication | affected 5.0.0-rc.0 5.0.0-rc.14 semver | Not specified |
| CNA | Team-alembic | Ash Authentication | affected f3a53f480088419788d5c3934af3131fa9066773 * git | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| osv.dev/vulnerability/EEF-CVE-2026-82760 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | osv.dev | |
| github.com/team-alembic/ash_authentication/commit/d5a5d4cb5cc17fbd6e2a12... | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| github.com/team-alembic/ash_authentication/security/advisories/GHSA-q876... | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| cna.erlef.org/cves/CVE-2026-82760.html | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | cna.erlef.org | |
| github.com/team-alembic/ash_authentication/commit/f3a53f480088419788d5c3... | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| github.com/team-alembic/ash_authentication/commit/dfb19c897853686ab481c5... | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Peter Ullrich (en)
CNA: James Harton (en)
CNA: Jonatan Männchen / EEF (en)
There are currently no legacy QID mappings associated with this CVE.