CVE-2025-8101
Description
A prototype pollution vulnerability was found in Linkify. This vulnerability allows an attacker to inject HTML attributes and manipulate user-controlled variables.
Statement
No Red Hat products or offerings are affected by this vulnerability.
This vulnerability is Important rather than Moderate because it enables a direct escalation from a logic flaw (prototype pollution) to active client-side code execution (XSS) in a single step, with no complex exploitation required. By failing to filter the proto property in the assign() helper, Linkify.js 4.3.1 allows attackers to inject malicious event handlers into Object.prototype, which are then automatically inherited and applied to all generated elements. This results in universal HTML attribute injection, enabling both stored and reflected XSS. Since Linkify is commonly used in contexts that render untrusted user input—such as comments, chat messages, and CMS content—this flaw can be exploited remotely and at scale, impacting every end-user who views the processed content.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.6 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | Low | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability
Technical Impact: Read Application Data; Modify Application Data
This weakness is usually exploited by using a special attribute of objects called proto, constructor, or prototype. Such attributes give access to the object prototype. An attacker can inject attributes that are used in other components by adding or modifying attributes of an object prototype. This creates attributes that exist on every object, or replace critical attributes with malicious ones. This can be problematic if the product depends on existence or non-existence of certain attributes, or uses pre-defined attributes of the object prototype (such as hasOwnProperty, toString, or valueOf).
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker can override existing attributes with ones that have incompatible type, which may lead to a crash.
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