What is the CVSS score of CVE-2021-45105?

CVE-2021-45105 has a CVSS 3.1 base score of 5.9 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 70.4%.

Which versions of Apache are affected by CVE-2021-45105?

CVE-2021-45105 presents moderate security risk, a input validation vulnerability rated CVSS 5.9. Exploitation could compromise the security of affected deployments.. A patch is available.

How to fix or mitigate CVE-2021-45105?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.

Apache CVE-2021-45105

MEDIUM

Improper Input Validation (CWE-20)

2021-12-18 security@apache.org

Denial Of Service Apache

5.9

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.9 MEDIUM

AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 26, 2026 - 11:19 vuln.today

Patch released

Nov 21, 2024 - 06:31 nvd

Patch available

CVE Published

Dec 18, 2021 - 12:15 nvd

MEDIUM 5.9

DescriptionCVE.org

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) 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, 2.12.3, and 2.3.1.

AnalysisAI

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups.

Technical ContextAI

A denial of service vulnerability allows an attacker to disrupt the normal functioning of a system, making it unavailable to legitimate users. This vulnerability is classified as Improper Input Validation (CWE-20).

RemediationAI

A vendor patch is available — apply it immediately. Implement rate limiting and input validation. Use timeout mechanisms for resource-intensive operations. Deploy DDoS protection where applicable.