---
id: CVE-2026-123201
title: buku through 5.1.1 SSRF via bukuserver fetch_data and network_handle API
summary: >-
  Buku (bukuserver) through 5.1.1 contains an unauthenticated server-side
  request forgery vulnerability that allows remote attackers to make the server
  request internal hosts by supplying a url parameter to /api/fetch_data or
  /api/network_…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-918
vendor: jarun
product: buku
affected:
  - buku <= 5.1.1
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T18:16:37.726Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-123201'
references:
  - url: 'https://github.com/jarun/buku/issues/910'
  - url: 'https://github.com/jarun/buku/pull/916'
  - url: >-
      https://github.com/jarun/buku/commit/13f6497afc974f02f1069b760772abe8815d1675
  - url: >-
      https://github.com/jarun/buku/blob/e232ac357cbba22fe69d6d6dfc0d35512a4cd313/bukuserver/api.py#L97-L105
  - url: >-
      https://github.com/jarun/buku/blob/e232ac357cbba22fe69d6d6dfc0d35512a4cd313/buku.py#L4057-L4084
  - url: >-
      https://www.vulncheck.com/advisories/buku-through-5.1.1-ssrf-via-bukuserver-fetch-data-and-network-handle-api
    label: >-
      VulnCheck Advisory: buku through 5.1.1 SSRF via bukuserver fetch_data and
      network_handle API
tags:
  - cve.org
ingestedAt: '2026-11-05T22:38:31.459Z'
---

## Overview

Buku (bukuserver) through 5.1.1 contains an unauthenticated server-side request forgery vulnerability that allows remote attackers to make the server request internal hosts by supplying a url parameter to /api/fetch_data or /api/network_handle. Attackers can target loopback, private, or cloud metadata IP addresses, which pass the weak is_bad_url() check and follow redirects, to discover internal services and read their page titles, descriptions, and keywords.

## Affected

- `buku <= 5.1.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.