Vulnerability advisory
CVE-2026-82760
Superlinear base62 decoding exhausts CPU and memory in AshAuthentication API key sign-in
Also known as EEF-CVE-2026-82760GHSA-q876-xr24-2mcx
- CVSS 4.0
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
Affected versions
Repository
| Affected commits | Fixed by commit |
|---|---|
| GIT github.com/team-alembic/ash_authentication ↗ | |
| f3a53f480088419788d5c3934af3131fa9066773 to before d5a5d4cb5cc17fbd6e2a120a6111b47accad4b8e | d5a5d4cb5cc17fbd6e2a120a6111b47accad4b8e |
| cf2095dda5d489ee37166cfce0905f6bd21f4761 to before d6b2be35cf8f0b8ab84e7a934cfb0d91de0a3c17 | d6b2be35cf8f0b8ab84e7a934cfb0d91de0a3c17 |
| 6767fe27eb952e5bc09aa2e5a7d8f96f5a1c424a to before fea75958a081ed337ceb578396174039694c48df | fea75958a081ed337ceb578396174039694c48df |
| Not specified | f3a53f480088419788d5c3934af3131fa9066773 |
| Not specified | dfb19c897853686ab481c5e773f7a1a0c74dea04 |
Also listed as affected (45)
| |
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.
References
- Webcna.erlef.org/cves/CVE-2026-82760.html ↗
- Webgithub.com ↗
- Webosv.dev/vulnerability/EEF-CVE-2026-82760 ↗
- Webrepo.hex.pm ↗
- Advisorygithub.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82760.json ↗
- Advisorygithub.com/team-alembic/ash_authentication/security/advisories/GHSA-q876-xr24-2mcx ↗
- Advisorynvd.nist.gov/vuln/detail/CVE-2026-82760 ↗
- Fixgithub.com/team-alembic/ash_authentication/commit/d5a5d4cb5cc17fbd6e2a120a6111b47accad4b8e ↗
- Fixgithub.com/team-alembic/ash_authentication/commit/dfb19c897853686ab481c5e773f7a1a0c74dea04 ↗
- Fixgithub.com/team-alembic/ash_authentication/commit/f3a53f480088419788d5c3934af3131fa9066773 ↗
- Packagegithub.com/team-alembic/ash_authentication ↗