CVE-2026-78391: ransomlook XSS (CVSS 8.8)

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.

Metrics

CVSS 4.0

8.8/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.44%

36.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
ransomlook	ransomlook	<= 2.0.0

References

https://github.com/RansomLook/RansomLook/commit/7efb59253f23552538f9a11c9bf21e7bcfcc1319

Timeline

Published: Aug 24, 2026
Last Modified: Oct 14, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-78391?

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.

How severe is CVE-2026-78391?

CVE-2026-78391 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.44% probability of exploitation in the next 30 days.

How do I fix CVE-2026-78391?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →