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

> Malicious web pages can bypass authorization checks to list, read, create, overwrite, or delete automation artifacts in the Summarize browser extension.

- **Severity:** Medium 5.3 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 18 May 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-5624-2pmv-jx46

## What is CVE-2026-45243?

CVE-2026-45243 is a medium-severity missing authorization vulnerability in steipete summarize, published on 18 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-45243?

2 open source packages ship an affected version, including @steipete/summarize. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@steipete/summarize` | npm | All versions | 0.15.0 |
| `@steipete/summarize` | npm | All versions | 0.15.0 |

Products: Steipete Summarize.

## How do I fix CVE-2026-45243?

Upgrade @steipete/summarize to 0.15.0 or later.

## Is CVE-2026-45243 being exploited?

There is no known exploitation of CVE-2026-45243 in the wild and no public exploit code.

## Other vulnerabilities in steipete summarize

- [CVE-2026-45242](https://insights.sbomify.com/CVE-2026-45242/): Summarize < 0.15.1 Path Traversal via slidesDir Parameter (high 7.1)
- [CVE-2026-45246](https://insights.sbomify.com/CVE-2026-45246/): Summarize < 0.15.1 Insecure File Permissions Information Disclosure (medium 6.8)
- [CVE-2026-45245](https://insights.sbomify.com/CVE-2026-45245/): Summarize < 0.15.1 Unauthorized Daemon Request via Untrusted Events (medium 4.6)
- [CVE-2026-45244](https://insights.sbomify.com/CVE-2026-45244/): Summarize < 0.15.1 Unapproved Browser Automation Execution (low 2.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45243 and fix it if it is affected.

What it is: CVE-2026-45243 is a medium-severity missing authorization vulnerability in steipete summarize, published on 18 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-45243 in the wild and no public exploit code.

Affected packages and fixed versions:
- @steipete/summarize (npm): affected all versions; fixed in 0.15.0
- @steipete/summarize (npm): affected all versions; fixed in 0.15.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-45243/ (Markdown: https://insights.sbomify.com/CVE-2026-45243/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45243
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45243
- OSV: https://osv.dev/vulnerability/CVE-2026-45243

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45243/
Summaries are generated and may contain mistakes; the official description above is the record.