Auth bypass in Steipete Summarize
CVE-2026-45243
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (24.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 24.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Steipete Summarize — versions 0, 357544063af535bd574752622f9eb94be33ee5fd
Weakness classification (CWE)
References
- github.com/steipete/summarize/releases/tag/v0.15.2 (release-notes, Release Notes)
- github.com/steipete/summarize/pull/222 (issue-tracking, Exploit, Patch, Issue Tracking)
- github.com/steipete/summarize/commit/357544063af535bd574752622f9eb94be33ee5fd (Patch, patch)
- www.vulncheck.com/advisories/summarize-browser-extension-missing-authorization-… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-45243?
- CVE-2026-45243 is a medium-severity vulnerability in Steipete Summarize, classified under Missing Authorization. CVSS score: 6.1/10. Published 2026-05-18.
- How severe is CVE-2026-45243?
- Medium severity. CVSS v3 base score is 6.1 out of 10.