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Apache Log4j2 vulnerable to Improper Input Validation and Uncontrolled Recursion

High severity GitHub Reviewed Published Dec 18, 2021 to the GitHub Advisory Database • Updated Jan 30, 2023

Package

maven org.apache.logging.log4j:log4j-core (Maven)

Affected versions

>= 2.4.0, < 2.12.3
>= 2.13.0, < 2.17.0
< 2.3.1

Patched versions

2.12.3
2.17.0
2.3.1

Description

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0 and 2.12.3.

Affected packages

Only the org.apache.logging.log4j:log4j-core package is directly affected by this vulnerability. The org.apache.logging.log4j:log4j-api should be kept at the same version as the org.apache.logging.log4j:log4j-core package to ensure compatability if in use.

References

Published by the National Vulnerability Database Dec 18, 2021
Reviewed Dec 18, 2021
Published to the GitHub Advisory Database Dec 18, 2021
Last updated Jan 30, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS score

95.660%
(100th percentile)

Weaknesses

CVE ID

CVE-2021-45105

GHSA ID

GHSA-p6xc-xr62-6r2g

Source code

No known source code

Credits

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