8.8
HIGH CVSS 4.0
CVE-2026-78391
Stored Cross-Site Scripting via Untrusted Cryptocurrency Address Rendering in RansomLook
Description

RansomLook contains a stored cross-site scripting (XSS) vulnerability in the cryptocurrency wallet detail view. Cryptocurrency addresses and blockchain names originating from external sources, including the public crowd-sourced ransomwhe.re feed, were stored without sufficient validation and later embedded directly into an inline JavaScript onclick handler. Although Jinja HTML autoescaping was applied, it does not provide adequate protection when untrusted data is inserted into a JavaScript string inside an HTML attribute. HTML entities such as ' are decoded by the browser's HTML parser before the resulting attribute is interpreted as JavaScript. Consequently, a specially crafted cryptocurrency address containing quote characters and JavaScript syntax could escape the intended string literal and execute arbitrary JavaScript when a user clicked the affected wallet's CSV export button. Because cryptocurrency information imported from an untrusted upstream could reach the vulnerable rendering path, exploitation may not require an authenticated RansomLook account if an attacker can introduce a malicious wallet record into a consumed external data source. Successful exploitation could allow attacker-controlled JavaScript to execute in the security context of the RansomLook web application, potentially exposing information accessible to the victim or performing actions with the victim's privileges. The patch mitigates the issue by validating cryptocurrency addresses and blockchain identifiers before storage, restricting them to a safe character set, and replacing the inline JavaScript handler with data-* attributes and an external event listener so wallet values are treated strictly as data rather than executable JavaScript.

INFO

Published Date :

Aug. 24, 2026, 2:13 p.m.

Last Modified :

Aug. 24, 2026, 2:13 p.m.

Remotely Exploit :

Yes !

Source :

CIRCL
Affected Products

The following products are affected by CVE-2026-78391 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 HIGH 5a6e4751-2f3f-4070-9419-94fb35b644e8
Solution
Validate and sanitize external data before storing and displaying to prevent XSS attacks.
  • Validate cryptocurrency addresses and blockchain identifiers.
  • Sanitize user-supplied input.
  • Avoid embedding untrusted data directly into JavaScript.
  • Use external event listeners for data handling.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-78391 vulnerability anywhere in the article.

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.