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NVD / CVE Program· CNA apache

CVE-2021-45105: Apache Log4j2 does not always protect from infinite recursion in lookup evaluation

Noroxi assessment

Priority: Plan (action score 53/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 99.9% (FIRST EPSS); higher than 99.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Apache Software Foundation Apache Log4j2 2.12.3, 2.3.1.
  • Mentioned 6 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Add it to your regular patch cycle. Upgrade to Apache Software Foundation Apache Log4j2 2.12.3, 2.3.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.9 · v3.1—Proof of concept Fix available
Published
Dec 18, 2021
Updated
Aug 25, 2026
EPSS
99.9% · 99th percentile

Report tools

JSON

Action score

53

Plan

Add it to your regular patch cycle.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
30 / 30 · 99.9%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
apachelog4j
netappcloud manager
debiandebian linux
sonicwallemail security
sonicwallnetwork security manager
sonicwallweb application firewall
sonicwall6bk1602-0aa12-0tp0 firmware
sonicwall6bk1602-0aa12-0tp0
sonicwall6bk1602-0aa22-0tp0 firmware
sonicwall6bk1602-0aa22-0tp0
sonicwall6bk1602-0aa32-0tp0 firmware
sonicwall6bk1602-0aa32-0tp0

and 109 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apache log4j2.13.0 and later · up to 2.16.0 inclusive
  • apache log4j2.0 and later · before 2.3.1
  • apache log4j2.4 and later · before 2.12.3
  • debian debian linux10.0
  • debian debian linux11.0
  • netapp cloud managerall versions
  • oracle agile engineering data management6.2.1.0
  • oracle agile plm mcad connector3.6
  • oracle agile product lifecycle management9.3.6
  • oracle autovue for agile product lifecycle management21.0.2
  • oracle banking deposits and lines of credit servicing2.12.0
  • oracle banking enterprise default management2.12.0
  • oracle banking enterprise default management2.7.1
  • oracle banking loans servicing2.12.0
  • oracle banking party management2.7.0
  • oracle banking payments14.5
  • oracle banking platform2.12.0
  • oracle banking platform2.6.2
  • oracle banking platform2.7.1
  • oracle banking trade finance14.5

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

  • Apache Software Foundation Apache Log4j2

    • log4j-core and later · before 2.17.0affectedfixed in 2.12.3, 2.3.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:10apache-log4j2before 2.17.0-1~deb10u12.17.0-1~deb10u1
Debian:11apache-log4j2before 2.17.0-1~deb11u12.17.0-1~deb11u1
Debian:12apache-log4j2before 2.17.0-12.17.0-1
Debian:9apache-log4j2before 2.12.3-0+deb9u12.12.3-0+deb9u1
Mavenorg.apache.logging.log4j:log4j-corefrom 2.13.0 · before 2.17.02.17.0
Mavenorg.apache.logging.log4j:log4j-corefrom 2.4.0 · before 2.12.32.12.3
Mavenorg.apache.logging.log4j:log4j-corebefore 2.3.12.3.1
Mavenorg.ops4j.pax.logging:pax-logging-log4j2from 1.10.0 · before 1.10.91.10.9
Mavenorg.ops4j.pax.logging:pax-logging-log4j2from 1.11.0 · before 1.11.121.11.12
Mavenorg.ops4j.pax.logging:pax-logging-log4j2from 1.8.0 · before 1.9.21.9.2
Mavenorg.ops4j.pax.logging:pax-logging-log4j2from 2.0.0 · before 2.0.132.0.13
openSUSE:Leap 15.2log4jbefore 2.17.0-lp152.3.12.12.17.0-lp152.3.12.1
openSUSE:Leap 15.3log4jbefore 2.17.0-4.13.12.17.0-4.13.1
Red Hat:jboss_enterprise_application_platform:7.4::el7eap7-log4jbefore 0:2.17.1-1.redhat_00001.1.el7eap0:2.17.1-1.redhat_00001.1.el7eap
Red Hat:jboss_enterprise_application_platform:7.4::el8eap7-log4jbefore 0:2.17.1-1.redhat_00001.1.el8eap0:2.17.1-1.redhat_00001.1.el8eap
Red Hat:red_hat_single_sign_on:7.5::el7rh-sso7-keycloakbefore 0:15.0.6-1.redhat_00001.1.el7sso0:15.0.6-1.redhat_00001.1.el7sso
Red Hat:red_hat_single_sign_on:7.5::el7rh-sso7-keycloak-serverbefore 0:15.0.6-1.redhat_00001.1.el7sso0:15.0.6-1.redhat_00001.1.el7sso
Red Hat:red_hat_single_sign_on:7.5::el8rh-sso7-keycloakbefore 0:15.0.6-1.redhat_00001.1.el8sso0:15.0.6-1.redhat_00001.1.el8sso
Red Hat:red_hat_single_sign_on:7.5::el8rh-sso7-keycloak-serverbefore 0:15.0.6-1.redhat_00001.1.el8sso0:15.0.6-1.redhat_00001.1.el8sso

Same product

apache: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-44228Apache Log4j2 JNDI features do not protect against attacker controlled LDAP and other JNDI related endpointsKEV
    100Now
  • CVE-2021-45046Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attackKEV
    96Now
  • CVE-2017-5645In Apache Log4j 2.x before 2.8.2, when using the TCP socket server or UDP socket server to receive serialized log events from another…
    66This week

Published before and after this one in the same product

  • ← EarlierCVE-2020-9488Apr 27, 2020 · Improper validation of certificate with host mismatch in Apache Log4j SMTP appender.
    16Monitor
  • ← EarlierCVE-2021-4104Dec 14, 2021 · Deserialization of untrusted data in JMSAppender in Apache Log4j 1.2
    54Plan
  • Later →CVE-2021-44832Dec 28, 2021 · Apache Log4j2 vulnerable to RCE via JDBC Appender when attacker controls configuration
    55Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Apache Software Foundation Apache Log4j22.12.3Vendor (CNA)
Apache Software Foundation Apache Log4j22.3.1Vendor (CNA)
debian:apache-log4j22.17.0-1 · Debian:12Package registry (OSV)
Maven:org.apache.logging.log4j:log4j-core2.12.3Package registry (OSV)
Maven:org.apache.logging.log4j:log4j-core2.17.0Package registry (OSV)
Maven:org.apache.logging.log4j:log4j-core2.3.1Package registry (OSV)
Maven:org.ops4j.pax.logging:pax-logging-log4j21.10.9Package registry (OSV)
Maven:org.ops4j.pax.logging:pax-logging-log4j21.11.12Package registry (OSV)
Maven:org.ops4j.pax.logging:pax-logging-log4j21.9.2Package registry (OSV)
Maven:org.ops4j.pax.logging:pax-logging-log4j22.0.13Package registry (OSV)
opensuse:log4j2.17.0-lp152.3.12.1 · openSUSE:Leap 15.2Package registry (OSV)
red hat:eap7-log4j0:2.17.1-1.redhat_00001.1.el7eap · Red Hat:jboss_enterprise_application_platform:7.4::el7Package registry (OSV)
red hat:rh-sso7-keycloak0:15.0.6-1.redhat_00001.1.el7sso · Red Hat:red_hat_single_sign_on:7.5::el7Package registry (OSV)
red hat:rh-sso7-keycloak-server0:15.0.6-1.redhat_00001.1.el7sso · Red Hat:red_hat_single_sign_on:7.5::el7Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×7

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:132021-12-18
Proof-of-concept repository on GitHubstars:02021-12-18
Proof-of-concept repository on GitHubstars:02021-12-19
Proof-of-concept repository on GitHubstars:32021-12-20
Proof-of-concept repository on GitHubstars:02021-12-23
Proof-of-concept repository on GitHubstars:22021-12-23
Proof-of-concept repository on GitHubstars:02022-04-03

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoCsame day
  2. Published
  3. TodayNov 11, 2026+1789 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-20 · Improper Input Validation

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (12 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records