Cyber Resilience

CVE-2026-42157

Medium

Published: 12 May 2026

Published
12 May 2026
Modified
18 May 2026
KEV Added
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Patch
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CVSS Score v4 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/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 Score 0.0018 39.9th percentile
Risk Priority 10 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-42157 is a medium-severity Cross-site Scripting (CWE-79) vulnerability. Its CVSS base score is 5.1 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 39.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Flowsint is an open-source OSINT graph exploration tool designed for cybersecurity investigation, transparency, and verification. Prior to 1.2.3, a remote attacker can create a map node with a malicious label that contains arbitrary HTML. When the map tab is selected…

more

and a map node marker is selected, it will render the arbitrary HTML, potentially triggering stored XSS. This vulnerability is fixed in 1.2.3.

CWE(s)
CWE-79

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1059.007 JavaScript Execution
Adversaries may abuse various implementations of JavaScript for execution.
attack.mitre.org →
Why these techniques?

Stored XSS in a web-based OSINT tool directly enables remote exploitation of a public-facing application (T1190) via arbitrary JavaScript execution in victim browsers (T1059.007).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

Affected Assets

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

SI-10 Information Input Validation
addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

SI-15 Information Output Filtering
addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

References