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CVE-2021-45105

Apache Log4j2 does not always protect from infinite recursion in lookup evaluation

Published: Dec 18, 2021Updated: May 29, 2026 Sources: CVE List NVD GHSA BDUCWE-20
NVD MITRE
5.9CVSSMEDIUM
EPSS Score
100.0%
Top 0.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

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.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-20CWE-674

Affected Products

OpenShift Container PlatformRed Hat Inc.
SaaSSaaS Service
Cloud & SaaS / container-orchestration
Jboss FuseRed Hat Inc.
On-premWeb App
DevTools & CI / build-test-tools
Debian GNU/LinuxСообщество свободного программного обеспечения
On-premOS
Operating Systems / linux-distro
JBoss Enterprise Application PlatformRed Hat Inc.
On-premWeb App
Enterprise Software / itsm-monitoring
OpenShift Application RuntimesRed Hat Inc.
MixedSaaS Service
Cloud & SaaS / cloud-platform
red hat inc.commercialUSOperating Systemsaka red hat
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf
and 136 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available
Workaround Available

MITRE ATT&CK

2 techniques
Impact
Initial Access
View detailed technique mapping

References

https://access.redhat.com/security/cve/CVE-2021-45105
access.redhat.com
https://logging.apache.org/log4j/2.x/security.html
logging.apache.org
https://redos.red-soft.ru/support/secure/
redos.red-soft.ru
and 29 more references View all →

Timeline

Published
Dec 18, 2021
Last Updated
May 29, 2026

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