Security Vulnerability CVE-2021-45046 - Complete Analysis and Details
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CVE-2021-45046

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This is a free service offered by Red Hot Cyber to the community. It allows you to view, on a single page, information about a single CVE from the National Vulnerability Database (NVD) and the National Institute of Standards and Technology (NIST) of the United States of America, the Forum of Incident Response and Security Teams (FIRST) regarding the EPSS score and percentile, data from the KEV catalog of the Cybersecurity and Infrastructure Security Agency (CISA), as well as selected resources from Red Hot Cyber and other international sources.

National Vulnerability Database Information

Description: It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.

CVSS Base Score: 9.0 (v3.1)

The **CVSS Base Score** is a score from **0 to 10** that represents the intrinsic severity of a vulnerability. A higher score indicates greater severity.

Value
0.02.55.07.510.0
Published on: 12/14/2021 19:15:07
Last modified: 10/27/2025 17:35:56
NIST: CVE source from the National Vulnerability Database (NVD)

CVSS Metrics Details

  • Base Severity: CRITICAL
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
  • Attack Vector: NETWORK
  • Attack Complexity: HIGH
  • Privileges Required: NONE
  • User Interaction: NONE
  • Scope: CHANGED
  • Confidentiality Impact: HIGH
  • Integrity Impact: HIGH
  • Availability Impact: HIGH

Common Weakness Enumeration (CWE)

Database CWE: v4.18

CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection') ↗

The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.

Fonte: MITRE CWE


FIRST Information

EPSS Score: 0.9434

The **EPSS (Exploit Prediction Scoring System)** is a score from **0 to 1** that indicates the **probability** that a vulnerability will be exploited in the real world in the next 30 days. A higher value indicates a greater likelihood of exploitation.

Value
0.00.250.50.751.0

Percentile: 0.9995

The **Percentile** indicates how much higher this vulnerability's EPSS score is compared to all other vulnerabilities in the EPSS database. For example, a percentile of 0.90 (90%) means that 90% of vulnerabilities have an EPSS score equal to or lower than the current one.

Value
0.00.250.50.751.0

*Data updated as of: 2025-12-19


CISA Information (Known Exploited Vulnerabilities)

The **CISA KEV Catalog** lists vulnerabilities that have been **actively exploited in the real world**. If a CVE is present in this catalog, it indicates that the threat is immediate and mitigation should be a top priority.

CVE **CVE-2021-45046** **IS PRESENT** in the CISA KEV Catalog!

  • Vulnerability Name: Apache Log4j2 Deserialization of Untrusted Data Vulnerability
  • Short Description: Apache Log4j2 contains a deserialization of untrusted data vulnerability due to the incomplete fix of CVE-2021-44228, where the Thread Context Lookup Pattern is vulnerable to remote code execution in certain non-default configurations.
  • Date Added to KEV: 05/01/2023
  • Vendor/Product: Apache / Log4j2
  • Required Action: Apply updates per vendor instructions.
  • Due Date: 05/22/2023


NVD References

Exploit PoC from GitHub

  • fox-it/log4j-finder: Find vulnerable Log4j2 versions on disk and also inside Java Archive Files (Log4Shell CVE-2021-44228, CVE-2021-45046, CVE-2021-45105)
  • cckuailong/Log4j_CVE-2021-45046: Log4j 2.15.0 Privilege Escalation -- CVE-2021-45046
  • alexbakker/log4shell-tools: Tool that runs a test to check whether one of your applications is affected by the recent vulnerabilities in log4j: CVE-2021-44228 and CVE-2021-45046
  • HynekPetrak/log4shell-finder: Fastest filesystem scanner for log4shell (CVE-2021-44228, CVE-2021-45046) and other vulnerable (CVE-2017-5645, CVE-2019-17571, CVE-2022-23305, CVE-2022-23307 ... ) instances of log4j library. Excellent performance and low memory footprint.
  • mergebase/log4j-detector: A public open sourced tool. Log4J scanner that detects vulnerable Log4J versions (CVE-2021-44228, CVE-2021-45046, etc) on your file-system within any application. It is able to even find Log4J instances that are hidden several layers deep. Works on Linux, Windows, and Mac, and everywhere else Java runs, too! TAG_OS_TOOL, OWNER_KELLY, DC_PUBLIC