XSS in Webrecorder Wabac.js

CVE-2025-58765

wabac.js provides a full web archive replay system, or 'wayback machine', using Service Workers. A Reflected Cross-Site Scripting (XSS) vulnerability exists in the 404 error handling logic of wabac.js v2.23.10 and below. The parameter `requestURL` (derived from the original request target) is directly embedded into an inline `<script>` block without sanitization or escaping. This allows an attacker to craft a malicious URL that executes arbitrary JavaScript in the victim’s browser. The scope may be limited by CORS policies, depending on the situation in which wabac.js is used. The vulnerability is fixed in wabac.js v2.23.11.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.003 (15.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 15.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-58765: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-58765?
CVE-2025-58765 is a high-severity vulnerability in Webrecorder Wabac.js, classified under Cross-site Scripting. CVSS score: 7.1/10. Published 2025-09-09.
How severe is CVE-2025-58765?
High severity. CVSS v3 base score is 7.1 out of 10.
Is CVE-2025-58765 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.