CVE-2026-8469

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

HIGH
8.2
CVSS Score
Published: May 20, 2026 at 01:35 PM UTC
Updated: July 23, 2026 at 07:31 PM UTC
1 product affected across 1 vendorPhoenix Storybook

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Severity
HIGH8.2
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.2.0 ≤ v < 1.1.00.2.0228669d55c23a754d1ef11f49a32121129d5395
Vendor states this is fixed in 96d524690af0fe197a49f60d18e564a620b9ef81 (fixed)
Affected range stops below 1.1.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

Related
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
https://cna.erlef.org/cves/CVE-2026-8469.html
Vendor AdvisoryRelated
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
https://github.com/phenixdigital/phoenix_storybook/security/advisories/GHSA-833p-95jq-929q
Related
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
https://osv.dev/vulnerability/EEF-CVE-2026-8469

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHEEF
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-770

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