VULNpocalypse

CVE-2026-57579: Alchemy: Unauthenticated nested page API leaks restricted & unpublished content

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-04 15:41 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

Alchemy is an open source content management system engine written in Ruby on Rails. Prior to 7.4.15, 8.0.15, 8.1.14, and 8.2.6, the unauthenticated GET /api/pages/nested endpoint implemented by Api::PagesController#nested in app/controllers/alchemy/api/pages_controller.rb returns an unfiltered page tree because it performs no authorization and does not scope descendants by the caller’s ability. Anonymous callers can retrieve restricted and unpublished page metadata that the sibling show action denies. When elements=true is supplied, PageTreeSerializer also returns element and ingredient content from restricted pages because PageTreePreloader and the serializer do not apply an ability check to those records. This issue is fixed in versions 7.4.15, 8.0.15, 8.1.14, and 8.2.6.

Description quoted from the CVE record (assigned by GitHub_M, published 2026-09-14).

Weakness: CWE-862: Missing Authorization

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity none, availability none. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: yes. Technical impact: partial.

Public exploit evidence (Exploit Observer)

Exploit Observer found 5 code repositories naming this CVE.

Code repositories that name a CVE are often scanners, copies or fakes, and some are malware. Read the code before running anything.

See all 7 references on Exploit Observer

Live scores

EPSS
0.006
low predicted chance of attack
VEDAS
0.988
strong exploit evidence
On CISA KEV
Not listed
Detection rule
Nuclei · Suricata

Who is affected

ProductAffectedNot affected
AlchemyCMS alchemy_cmsversion < 7.4.15
version >= 8.0.0, < 8.0.15
version >= 8.1.0, < 8.1.14
version >= 8.2.0, < 8.2.6		Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.

How to detect it

Nuclei template (active check)

Alchemy CMS - Unauthenticated Page Tree Information Disclosure

Alchemy is an open source CMS engine for Ruby on Rails. Prior to 7.4.15, 8.0.15, 8.1.14 and 8.2.6 the unauthenticated endpoint GET /api/pages/nested, implemented by Api::PagesController#nested, returns an unfiltered page tree because it performs no authorization and does not scope descendants by the caller’s ability. Anonymous callers can retrieve restricted and unpublished page metadata (name, slug, url_path, page_layout, public and restricted flags) that the sibling show action denies, and when elements=true is supplied PageTreeSerializer additionally returns element and ingredient content from restricted pages. This template requests the nested page tree without authentication and confirms the exposure by matching the PageTreeSerializer JSON structure; fixed versions add an ability check and reject anonymous callers.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (GET /api/pages/nested?elements=true); it decides using status, word matchers. Severity in the template: high. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2026-57579.yaml
Show the template (50 lines)
yaml
id: CVE-2026-57579

info:
  name: "Alchemy CMS - Unauthenticated Page Tree Information Disclosure"
  author: vedas-arpsyndicate
  severity: high
  description: |
    Alchemy is an open source CMS engine for Ruby on Rails. Prior to 7.4.15, 8.0.15, 8.1.14
    and 8.2.6 the unauthenticated endpoint GET /api/pages/nested, implemented by
    Api::PagesController#nested, returns an unfiltered page tree because it performs no
    authorization and does not scope descendants by the caller's ability. Anonymous callers can
    retrieve restricted and unpublished page metadata (name, slug, url_path, page_layout,
    public and restricted flags) that the sibling show action denies, and when elements=true is
    supplied PageTreeSerializer additionally returns element and ingredient content from
    restricted pages. This template requests the nested page tree without authentication and
    confirms the exposure by matching the PageTreeSerializer JSON structure; fixed versions add
    an ability check and reject anonymous callers.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-57579&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=alchemy&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2026-57579
    cwe-id: CWE-862
  metadata:
    verified: false
  tags: cve,cve2026,alchemy,auth-bypass,exposure,unauth

http:
  - method: GET
    path:
      - "{{BaseURL}}/api/pages/nested?elements=true"
    matchers-condition: and
    matchers:
      - type: word
        part: body
        condition: and
        words:
          - '"pages"'
          - '"page_layout"'
          - '"url_path"'
          - '"restricted"'
      - type: word
        part: header
        words:
          - "application/json"
      - type: status
        status:
          - 200

CVE-2026-57579.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-57579 Alchemy CMS Unauthenticated Nested Page Tree Disclosure. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"VEDAS CVE-2026-57579 Alchemy CMS Unauthenticated Nested Page Tree Disclosure"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/api/pages/nested"; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2026-57579; reference:url,https://www.exploit.observer/?keyword=CVE-2026-57579&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=alchemy&match=exact; sid:1096801; rev:1;)

CVE-2026-57579.rules on GitHub

References

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.

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