CVE-2026-49844
Description
A flaw was found in Apache Log4j API. This vulnerability occurs due to improper encoding of non-finite floating-point values during JSON serialization of MapMessages, leading to invalid JSON output. An attacker who can supply a non-finite value can exploit this to cause the affected logging layout to emit malformed JSON. This can corrupt log records or disrupt downstream log ingestion and parsing, potentially leading to a Denial of Service (DoS) or information integrity issues.
Statement
Important: Apache Log4j API in Red Hat products is affected by improper encoding of non-finite floating-point values during MapMessage JSON serialization. This flaw can lead to malformed JSON output when applications utilize JsonTemplateLayout or similar JSON serialization methods and process attacker-controlled floating-point values. The resulting invalid JSON may disrupt downstream log processing or corrupt log records, requiring specific application configurations for exploitation.
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 | 5.9 | 5.9 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Modify Application Data; Execute Unauthorized Code or Commands
An attacker could modify the structure of the message or data being sent to the downstream component, possibly injecting commands.
Frequently Asked Questions
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