CVE-2025-66287

High

Published: 04 December 2025

Published

04 December 2025

Modified

15 April 2026

KEV Added

—

Patch

—

CVSS Score 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Score 0.0005 14.3th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-66287 is a high-severity Classic Buffer Overflow (CWE-120) vulnerability in Webkitgtk (inferred from references). Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 14.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Client Execution (T1203). What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Directly remediates the WebKitGTK memory handling flaw (CWE-120) by requiring timely application of vendor patches such as those issued in RHSA-2025 advisories.

SI-16 Memory Protection good match

prevent

Implements memory protections like ASLR, DEP, and stack guards to prevent exploitation of buffer copy without size checking vulnerabilities in WebKitGTK.

SI-10 Information Input Validation partial match

prevent

Validates web content inputs to WebKitGTK to restrict malformed or oversized data that could trigger the improper memory handling leading to process crashes.

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution

Adversaries may exploit software vulnerabilities in client applications to execute code.

attack.mitre.org →

Why these techniques?

The vulnerability in WebKitGTK allows remote exploitation via malicious web content requiring user interaction, directly enabling Exploitation for Client Execution (T1203) through buffer overflow leading to process compromise.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD Description

A flaw was found in WebKitGTK. Processing malicious web content can cause an unexpected process crash due to improper memory handling.

Deeper analysisAI

CVE-2025-66287 is a vulnerability in WebKitGTK that allows processing of malicious web content to trigger an unexpected process crash due to improper memory handling, mapped to CWE-120 (Buffer Copy without Checking Size of Input). Published on 2025-12-04, it carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H), indicating high severity with significant potential impacts across confidentiality, integrity, and availability.

Remote attackers require no privileges and can exploit this over the network with low attack complexity, but it necessitates user interaction, such as visiting a malicious webpage or opening crafted content in an affected application. Exploitation leads to process crashes and, per the CVSS metrics, high-level compromise of confidentiality, integrity, and availability, potentially enabling broader system impacts depending on the context of WebKitGTK usage.

Red Hat has issued multiple security advisories with patches addressing this vulnerability, including RHSA-2025:22789, RHSA-2025:22790, RHSA-2025:23110, RHSA-2025:23433, and RHSA-2025:23434, recommending affected users apply the updates promptly to mitigate risks.