CVE-2026-8467

CRITICALNVD 9.59.5—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.5 under NVD CVSS v3. EPSS exploit probability: 0.9%, top 45% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
9.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Code Injection vulnerability in phenixdigital phoenix_storybook allows unauthenticated remote code execution via unsanitized attribute value interpolation in HEEx template generation.

The psb-assign WebSocket event handler in 'Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive':handle_event/3 accepts arbitrary attribute names and values from unauthenticated clients. These values are passed to 'Elixir.PhoenixStorybook.Helpers.ExtraAssignsHelpers':handle_set_variation_assign/3, which stores them verbatim. When rendering, 'Elixir.PhoenixStorybook.Rendering.ComponentRenderer':attributes_markup/1 interpolates binary attribute values directly into a HEEx template string as name="" without escaping double quotes or HEEx expression delimiters. An attacker can supply a value containing a closing quote followed by a HEEx expression block (e.g. foo" injected={EXPR} bar="), which causes EXPR to be treated as an inline Elixir expression. The resulting template is compiled via EEx.compile_string/2 and executed via Code.eval_quoted_with_env/3 with full Kernel imports and no sandbox, giving the attacker arbitrary code execution on the server.

This issue affects phoenix_storybook from 0.5.0 before 1.1.0.

CVSS v3
9.5
EG Score
9.5(medium)
EPSS
55.9%
KEV
Not listed

Published

May 20, 2026

Last Modified

May 21, 2026

Advisory Details (4)

Auto-updated May 20, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/EEF-CVE-2026-8467
github Patch Available🟡 PoC Available

Unauthenticated remote code execution via HEEx template injection in phoenix_storybook playground · Advisory · phenixdigital/phoenix_storybook · GitHub

https://github.com/phenixdigital/phoenix_storybook/security/advisories/GHSA-55hg-8qxv-qj4p
generic

Fix unsafe HEEx attribute generation in playground rendering · phenixdigital/phoenix_storybook@56ab846 · GitHub

https://github.com/phenixdigital/phoenix_storybook/commit/56ab8464d4375fa52db806148a06cce126ad481d
generic

Unauthenticated remote code execution via HEEx template injection in phoenix_storybook playground | Erlang Ecosystem Foundation CNA

https://cna.erlef.org/cves/CVE-2026-8467.html

Vendor Advisories for CVE-2026-8467(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Hex(1)
PackageVulnerable rangeFixed inDependents
phoenix_storybook0.5.0 ... 1.0.0 (25 versions)1.1.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 33× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-16 17:03 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 02:00 UTCEPSS rescore
  4. 2026-07-13 22:31 UTCEPSS rescore
  5. 2026-07-13 06:13 UTCEPSS rescore
  6. 2026-07-12 05:46 UTCEPSS rescore
  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-08 15:16 UTCEPSS rescore
  10. 2026-07-07 13:46 UTCEPSS rescore
  11. 2026-07-07 13:46 UTCEPSS rescore
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-06 16:27 UTCEPSS rescore
  14. 2026-07-06 02:23 UTCEPSS rescore
  15. 2026-07-06 02:23 UTCEPSS rescore
  16. 2026-07-05 02:31 UTCEPSS rescore
  17. 2026-07-05 02:30 UTCEPSS rescore
  18. 2026-07-04 06:31 UTCEPSS rescore
  19. 2026-07-04 06:31 UTCEPSS rescore
  20. 2026-07-01 15:07 UTCEPSS rescore
  21. 2026-06-30 23:22 UTCEPSS rescore
  22. 2026-06-29 14:06 UTCEPSS rescore
  23. 2026-06-28 04:56 UTCEPSS rescore
  24. 2026-06-27 03:08 UTCEPSS rescore
  25. 2026-06-25 13:50 UTCEPSS rescore
Show 36 more
  1. 2026-06-24 14:05 UTCEPSS rescore
  2. 2026-06-23 21:33 UTCEPSS rescore
  3. 2026-06-22 14:25 UTCEPSS rescore
  4. 2026-06-21 14:56 UTCEPSS rescore
  5. 2026-06-21 01:59 UTCEPSS rescore
  6. 2026-06-19 19:26 UTCEPSS rescore
  7. 2026-06-18 17:52 UTCEPSS rescore
  8. 2026-06-17 17:53 UTCEPSS rescore
  9. 2026-06-16 17:53 UTCEPSS rescore
  10. 2026-06-15 17:49 UTCEPSS rescore
  11. 2026-06-15 17:49 UTCEPSS rescore
  12. 2026-06-14 23:18 UTCEPSS rescore
  13. 2026-06-13 23:00 UTCEPSS rescore
  14. 2026-06-12 23:12 UTCEPSS rescore
  15. 2026-06-12 23:12 UTCEPSS rescore
  16. 2026-06-11 14:00 UTCEPSS rescore
  17. 2026-06-10 22:19 UTCEPSS rescore
  18. 2026-06-10 13:22 UTCEPSS rescore
  19. 2026-06-08 14:17 UTCEPSS rescore
  20. 2026-06-07 15:25 UTCEPSS rescore
  21. 2026-06-06 13:47 UTCEPSS rescore
  22. 2026-06-05 22:47 UTCEPSS rescore
  23. 2026-06-05 06:10 UTCEPSS rescore
  24. 2026-06-04 13:12 UTCEPSS rescore
  25. 2026-06-02 20:13 UTCEPSS rescore
  26. 2026-06-01 13:52 UTCEPSS rescore
  27. 2026-05-31 22:30 UTCEPSS rescore
  28. 2026-05-31 00:16 UTCEPSS rescore
  29. 2026-05-29 13:44 UTCEPSS rescore
  30. 2026-05-28 13:44 UTCEPSS rescore
  31. 2026-05-27 13:40 UTCEPSS rescore
  32. 2026-05-27 13:40 UTCEPSS rescore
  33. 2026-05-26 13:44 UTCEPSS rescore
  34. 2026-05-26 07:18 UTCEPSS rescore
  35. 2026-05-21 22:43 UTCEPSS rescore
  36. 2026-05-20 15:36 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-8467?
CVE-2026-8467 is a critical vulnerability published on May 20, 2026. Code Injection vulnerability in phenixdigital phoenix_storybook allows unauthenticated remote code execution via unsanitized attribute value interpolation in HEEx template generation. The psb-assign WebSocket event handler in 'Elixir.PhoenixStorybook.Story.PlaygroundPreviewLive':handleevent/3…
When was CVE-2026-8467 disclosed?
CVE-2026-8467 was first published in the National Vulnerability Database on May 20, 2026, with the most recent update on May 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8467 actively exploited?
CVE-2026-8467 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 55.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-8467?
CVE-2026-8467 has a CVSS v3 base score of 9.5 (NVD).
How do I remediate CVE-2026-8467?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8467, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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