CVE-2026-90769: lfnovo open-notebook advisory

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.

What it is

Open Notebook before 1.11.0 fails to validate the URL parameter in POST /api/sources endpoint, allowing authenticated users to perform server-side requests to internal services. Attackers can supply arbitrary URLs to read cloud metadata, internal network services, and localhost-bound services through the application server’s direct HTTP requests.

Description quoted from the CVE record (assigned by VulnCheck, published 2026-09-13).

Weakness: Server-Side Request Forgery (SSRF)

How it can be exploited

Exploitable over the network with low attack complexity with no special attack requirements needing low privileges and no user interaction. Impact: confidentiality high, integrity none, availability none. CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: no. Technical impact: partial.

Public exploit evidence (Exploit Observer)

Also known as: EUVD-2026-76990, GHSA-wr7p-6rrg-8m28

VEDAS cluster: VEDAS:DESERTGUST

Exploit Observer links 5 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (5)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Vulnerability databases and vendor advisories (3)

Catalogue entries, not exploit evidence.

Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2026-76990
Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-wr7p-6rrg-8m28
Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-90769

2 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS: 0.004
low predicted chance of attack
VEDAS: 0.986
strong exploit evidence
On CISA KEV: Not listed
Detection rule: Nuclei · Suricata

Who is affected

Product	Affected	Not affected
lfnovo open-notebook	before 1.11.0	Not stated

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

How to fix it

Fixed versions stated in the CVE record: 1.11.0.

Vendor guidance:

https://github.com/lfnovo/open-notebook/commit/9045ea50196927eac7de647bb5b7009349236fb4 (patch)

How to detect it

Nuclei template (active check)

Open Notebook - Server-Side Request Forgery
Open Notebook before 1.11.0 does not validate the user-supplied URL in the POST /api/sources endpoint (api/routers/sources.py). When a source of type “link” is created, the application server fetches the supplied url directly, allowing an attacker to coerce server-side requests to internal services, localhost-bound services, or cloud metadata endpoints. This template submits a link source pointing at an out-of-band collaborator host and confirms the SSRF from the resulting interaction.

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

The template sends 1 request (POST /api/sources); it confirms through an out-of-band callback (interactsh), so the scanner must be able to receive it; it decides using 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-2026-90769.yaml

Show the template (41 lines)

yaml

id: CVE-2026-90769

info:
  name: "Open Notebook - Server-Side Request Forgery"
  author: vedas-arpsyndicate
  severity: high
  description: |
    Open Notebook before 1.11.0 does not validate the user-supplied URL in the
    POST /api/sources endpoint (api/routers/sources.py). When a source of type
    "link" is created, the application server fetches the supplied url directly,
    allowing an attacker to coerce server-side requests to internal services,
    localhost-bound services, or cloud metadata endpoints. This template submits
    a link source pointing at an out-of-band collaborator host and confirms the
    SSRF from the resulting interaction.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-90769&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=open-notebook&match=exact
  classification:
    cvss-metrics: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
    cvss-score: 8.3
    cve-id: CVE-2026-90769
    cwe-id: CWE-918
  metadata:
    verified: false
    max-request: 1
  tags: cve,cve2026,open-notebook,ssrf,oast

http:
  - raw:
      - |
        POST /api/sources HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json

        {"type":"link","url":"http://{{interactsh-url}}"}

    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - "http"

CVE-2026-90769.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-90769 Open Notebook - Server-Side Request Forgery. Add them to your Suricata rule set and reload.

Show the rules

suricata

alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-90769 Open Notebook - Server-Side Request Forgery"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/api/sources"; nocase; fast_pattern; http.request_body; content:"\"url\""; nocase; pcre:"/\"url\"\s*:\s*\"https?:\/\/(?:169\.254\.169\.254|metadata|127\.0\.0\.1|0\.0\.0\.0|localhost|10\.|192\.168\.|172\.(?:1[6-9]|2[0-9]|3[01])\.)/i"; classtype:web-application-attack; reference:cve,CVE-2026-90769; reference:url,https://www.exploit.observer/?keyword=CVE-2026-90769&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=open-notebook&match=exact; sid:1095000; rev:1;)

CVE-2026-90769.rules on GitHub

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.