CVE-2026-8469 PUBLISHED

Unauthenticated denial-of-service via BEAM atom table exhaustion in phoenix_storybook

Assigner: EEF
Reserved: 13.05.2026 Published: 20.05.2026 Updated: 20.05.2026

Allocation of Resources Without Limits or Throttling vulnerability in phenixdigital phoenix_storybook allows unauthenticated denial-of-service via BEAM atom table exhaustion.

Multiple LiveView event handlers convert user-supplied event parameter strings to atoms using String.to_atom/1 without validation: 'Elixir.PhoenixStorybook.ExtraAssignsHelpers':handle_set_variation_assign/3 interns every key of the psb-assign params map; 'Elixir.PhoenixStorybook.ExtraAssignsHelpers':handle_toggle_variation_assign/3 interns the "attr" value from psb-toggle events; 'Elixir.PhoenixStorybook.ExtraAssignsHelpers':to_variation_id/2 interns elements of "variation_id"; and 'Elixir.PhoenixStorybook.ExtraAssignsHelpers':to_value/4 interns raw string values for attributes declared as :atom or :boolean. BEAM atoms are never garbage-collected, so each unique attacker-controlled string is a permanent allocation. Once the atom table ceiling (~1,048,576 atoms) is reached, the entire BEAM node aborts, taking down all applications running on it.

This issue affects phoenix_storybook from 0.2.0 before 1.1.0.

Metrics

CVSS 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
CVSS Score: 8.2

Product Status

Vendor phenixdigital
Product phoenix_storybook
Versions Default: unaffected
  • affected from 0.2.0 to 1.1.0 (excl.)
Vendor phenixdigital
Product phoenix_storybook
Versions Default: unaffected
  • affected from 0228669d55c23a754d1ef11f49a32121129d5395 to 96d524690af0fe197a49f60d18e564a620b9ef81 (excl.)

Affected Configurations

Phoenix Storybook must be mounted on a network-reachable route.

Credits

  • Peter Ullrich finder
  • Christian Blavier remediation developer
  • Jonatan Männchen analyst

References

Problem Types

  • CWE-770 Allocation of Resources Without Limits or Throttling CWE

Impacts

  • CAPEC-130 Excessive Allocation