---
id: "CVE-2026-121627"
kind: "vulnerability"
aliases: ["CVE-2026-121627"]
title: "buku: stored cross-site scripting in bookmark list via unescaped URL"
severity: "medium"
cvss: 6.1
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["buku", "bukuserver", "package", "python"]
not_affected_if: ["bukuserver-not-deployed", "cli-only"]
published_at: "2026-11-03T18:17:58+00:00"
first_seen_at: "2026-11-03T18:22:10+00:00"
updated_at: "2026-11-03T18:22:41+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121627", "first_seen_at": "2026-11-03T18:22:10+00:00"}]
---

# buku: stored cross-site scripting in bookmark list via unescaped URL

Buku is a command-line bookmark manager, and its bukuserver web interface fails to escape bookmark URLs in the bookmark list. An attacker who submits a crafted bookmark URL through the unauthenticated /api/bookmarks endpoint can run script in a viewer's browser and make same-origin API requests using that viewer's credentials.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed buku version with `buku --version` or `pip show buku`; the flaw affects versions 5.0 through 5.1.1.
- Confirm whether bukuserver is running and reachable (the web bookmark list), since the flaw is in that web interface.
- Check whether /api/bookmarks accepts unauthenticated requests on the deployment.

## Fix

- buku: unknown (the sources do not state a fixed version)

## Timeline

- 2026-11-03T18:22:10+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121627

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/buku-5.0-through-5.1.1-stored-xss-via-bukuserver-bookmark-list-url

## From the sources

buku 5.0 through 5.1.1 contains a stored cross-site scripting vulnerability in the bukuserver bookmark list that allows attackers to execute script via an unescaped bookmark URL in BookmarkModelView._list_entry(). Attackers can submit a URL containing a double quote and event handler through the unauthenticated /api/bookmarks endpoint to issue same-origin API requests with viewers' credentials.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_