CVE-2026-34477

Description

A flaw was found in Apache Log4j Core. A network-based attacker can perform a man-in-the-middle (MITM) attack, allowing them to intercept encrypted communications. This occurs when an SMTP, Socket, or Syslog appender uses Transport Layer Security (TLS) with a nested element, and the attacker has a certificate from a trusted Certificate Authority (CA). The vulnerability stems from an incomplete hostname verification fix, making TLS connections susceptible to interception.

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).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score6.85.9N/A
Attack VectorNetworkNetworkN/A
Attack ComplexityHighHighN/A
Privileges RequiredLowNoneN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityHighNoneN/A
Integrity ImpactHighHighN/A
Availability ImpactNoneNoneN/A

Vector

Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/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)

CWE-295

Integrity,Authentication

Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity

When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. The product might connect to a malicious host while believing it is a trusted host, or the product might be deceived into accepting spoofed data that appears to originate from a trusted host.

Frequently Asked Questions

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