Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack
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.
- Published
- Dec 14, 2021
- Updated
- Jun 17, 2026
- EPSS
- 100.0% · 100th percentile
- CWE
- CWE-917
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Report tools
Action score
96
Now
Patch today or shut off access.
- CVSS
- 36 / 40 · 9.0 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 30 / 30 · 100.0%
CISA SSVC decision
- Exploitation
- active
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on May 1, 2023. That signals real attacks, not theory.
Remediation deadline for government agencies: May 22, 2023.
Known to be used in ransomware campaigns.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| apache | log4j | cpe:2.3:a:apache:log4j |
| cvat | computer vision annotation tool | cpe:2.3:a:cvat:computer_vision_annotation_tool |
| intel | audio development kit | cpe:2.3:a:intel:audio_development_kit |
| intel | datacenter manager | cpe:2.3:a:intel:datacenter_manager |
| intel | genomics kernel library | cpe:2.3:a:intel:genomics_kernel_library |
| intel | oneapi | cpe:2.3:a:intel:oneapi |
| intel | secure device onboard | cpe:2.3:a:intel:secure_device_onboard |
| intel | sensor solution firmware development kit | cpe:2.3:a:intel:sensor_solution_firmware_development_kit |
| intel | system debugger | cpe:2.3:a:intel:system_debugger |
| intel | system studio | cpe:2.3:a:intel:system_studio |
| siemens | sppa-t3000 ses3000 firmware | cpe:2.3:o:siemens:sppa-t3000_ses3000_firmware |
| siemens | sppa-t3000 ses3000 | cpe:2.3:h:siemens:sppa-t3000_ses3000 |
and 49 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apache log4j2.0.1 and later · before 2.12.2
- apache log4j2.13.0 and later · before 2.16.0
- apache log4j2.0
- cvat computer vision annotation toolall versions
- debian debian linux10.0
- debian debian linux11.0
- fedoraproject fedora34
- fedoraproject fedora35
- intel audio development kitall versions
- intel datacenter managerall versions
- intel genomics kernel libraryall versions
- intel oneapiall versions
- intel secure device onboardall versions
- intel sensor solution firmware development kitall versions
- intel system debuggerall versions
- intel system studioall versions
- siemens 6bk1602-0aa12-0tp0 firmwarebefore 2.7.0
- siemens 6bk1602-0aa22-0tp0 firmwarebefore 2.7.0
- siemens 6bk1602-0aa32-0tp0 firmwarebefore 2.7.0
- siemens 6bk1602-0aa42-0tp0 firmwarebefore 2.7.0
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 Log4j
- Apache Log4j2 and later · before 2.16.0affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:10 | apache-log4j2 | before 2.16.0-1~deb10u1 | 2.16.0-1~deb10u1 |
| Debian:11 | apache-log4j2 | before 2.16.0-1~deb11u1 | 2.16.0-1~deb11u1 |
| Debian:12 | apache-log4j2 | before 2.16.0-1 | 2.16.0-1 |
| Maven | org.apache.logging.log4j:log4j-core | from 2.13.0 · before 2.16.0 | 2.16.0 |
| Maven | org.apache.logging.log4j:log4j-core | before 2.12.2 | 2.12.2 |
| Maven | org.ops4j.pax.logging:pax-logging-log4j2 | from 1.10.0 · before 1.10.8 | 1.10.8 |
| Maven | org.ops4j.pax.logging:pax-logging-log4j2 | from 1.11.0 · before 1.11.11 | 1.11.11 |
| Maven | org.ops4j.pax.logging:pax-logging-log4j2 | from 1.8.0 · before 1.9.2 | 1.9.2 |
| Maven | org.ops4j.pax.logging:pax-logging-log4j2 | from 2.0.0 · before 2.0.12 | 2.0.12 |
| openSUSE:Leap 15.2 | disruptor | before 3.4.4-lp152.2.3.1 | 3.4.4-lp152.2.3.1 |
| openSUSE:Leap 15.2 | jakarta-servlet | before 5.0.0-lp152.2.1 | 5.0.0-lp152.2.1 |
| openSUSE:Leap 15.2 | log4j | before 2.16.0-lp152.3.9.1 | 2.16.0-lp152.3.9.1 |
| openSUSE:Leap 15.3 | disruptor | before 3.4.4-3.3.1 | 3.4.4-3.3.1 |
| openSUSE:Leap 15.3 | jakarta-servlet | before 5.0.0-5.3.1 | 5.0.0-5.3.1 |
| openSUSE:Leap 15.3 | log4j | before 2.13.0-4.6.1 | 2.13.0-4.6.1 |
| openSUSE:Leap 15.3 | log4j | before 2.16.0-4.10.1 | 2.16.0-4.10.1 |
| openSUSE:Tumbleweed | log4j | before 2.16.0-2.1 | 2.16.0-2.1 |
| Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | eap7-apache-cxf | before 0:3.1.16-4.redhat_00003.1.ep7.el7 | 0:3.1.16-4.redhat_00003.1.ep7.el7 |
| Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | eap7-apache-cxf-rt | before 0:3.1.16-4.redhat_00003.1.ep7.el7 | 0:3.1.16-4.redhat_00003.1.ep7.el7 |
| Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | eap7-apache-cxf-services | before 0:3.1.16-4.redhat_00003.1.ep7.el7 | 0:3.1.16-4.redhat_00003.1.ep7.el7 |
| Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | eap7-apache-cxf-tools | before 0:3.1.16-4.redhat_00003.1.ep7.el7 | 0:3.1.16-4.redhat_00003.1.ep7.el7 |
| Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | eap7-jackson-databind | before 0:2.8.11.6-2.SP1_redhat_00002.1.ep7.el7 | 0:2.8.11.6-2.SP1_redhat_00002.1.ep7.el7 |
| Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | eap7-jettison | before 0:1.3.8-2.redhat_00002.1.ep7.el7 | 0:1.3.8-2.redhat_00002.1.ep7.el7 |
| Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | eap7-netty | before 0:4.1.63-1.Final_redhat_00002.1.ep7.el7 | 0:4.1.63-1.Final_redhat_00002.1.ep7.el7 |
+65
Same product
apache: all recordsOther 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 endpointsKEV100Now
- 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 applic66This week
- CVE-2019-17571Included in Log4j 1.2 is a SocketServer class that is vulnerable to deserialization of untrusted data which can be exploited to remotely exe60This week
- CVE-2022-23305SQL injection in JDBC Appender in Apache Log4j V159Plan
- CVE-2021-44832Apache Log4j2 vulnerable to RCE via JDBC Appender when attacker controls configuration55Plan
- CVE-2022-23302Deserialization of untrusted data in JMSSink in Apache Log4j 1.x54Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Debian:apache-log4j2 | 2.16.0-1 · Debian:12 | Package registry (OSV) |
| Maven:org.apache.logging.log4j:log4j-core | 2.12.2 | Package registry (OSV) |
| Maven:org.apache.logging.log4j:log4j-core | 2.16.0 | Package registry (OSV) |
| Maven:org.ops4j.pax.logging:pax-logging-log4j2 | 1.10.8 | Package registry (OSV) |
| Maven:org.ops4j.pax.logging:pax-logging-log4j2 | 1.11.11 | Package registry (OSV) |
| Maven:org.ops4j.pax.logging:pax-logging-log4j2 | 1.9.2 | Package registry (OSV) |
| Maven:org.ops4j.pax.logging:pax-logging-log4j2 | 2.0.12 | Package registry (OSV) |
| openSUSE:disruptor | 3.4.4-lp152.2.3.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| openSUSE:jakarta-servlet | 5.0.0-lp152.2.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| openSUSE:log4j | 2.16.0-lp152.3.9.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| Red Hat:eap7-jackson-databind | 0:2.8.11.6-2.SP1_redhat_00002.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-log4j | 0:2.17.1-1.redhat_00001.1.el7eap · Red Hat:jboss_enterprise_application_platform:7.4::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-atom-provider | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-cdi | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-client | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-crypto | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-jackson-provider | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-jackson2-provider | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-jaxb-provider | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-jaxrs | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
| Red Hat:eap7-resteasy-jettison-provider | 0:3.0.27-1.Final_redhat_00001.1.ep7.el7 · Red Hat:jboss_enterprise_application_platform_eus:7.1::el7 | Package registry (OSV) |
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Metasploit module ×1
- Nuclei detection template ×3
- Proof-of-concept repository on GitHub ×11
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.
| Source | Kind | Date |
|---|---|---|
| Metasploit module | auxiliary/scanner/http/log4shell_scannerLog4Shell HTTP Scannerauxiliary | 2021-12-09 |
| Nuclei detection template | Nuclei template CVE-2021-45046-DAST | — |
| Nuclei detection template | Nuclei template CVE-2021-45046 | — |
| Nuclei detection template | Nuclei template vrealize-operations-log4j-rce | — |
| Proof-of-concept repository on GitHub | stars:22 | 2021-12-15 |
| Proof-of-concept repository on GitHub | stars:4 | 2021-12-15 |
| Proof-of-concept repository on GitHub | stars:0 | 2021-12-15 |
| Proof-of-concept repository on GitHub | stars:0 | 2021-12-15 |
| Proof-of-concept repository on GitHub | stars:14 | 2021-12-16 |
| Proof-of-concept repository on GitHub | stars:0 | 2021-12-17 |
| Proof-of-concept repository on GitHub | stars:1 | 2021-12-18 |
| Proof-of-concept repository on GitHub | stars:85 | 2021-12-20 |
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.
- Metasploit-6 d
- Published
- First PoCsame day
- CISA KEV+502 d
- TodaySep 29, 2026+1750 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
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 researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
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
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
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
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-917 · Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.openwall.com/lists/oss-security/2021/12/14/4
- www.openwall.com/lists/oss-security/2021/12/15/3
- www.openwall.com/lists/oss-security/2021/12/18/1
- cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf
- cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf
- cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf
- cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/
- logging.apache.org/log4j/2.x/security.html
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032
- security.gentoo.org/glsa/202310-16
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd
- www.cve.org/CVERecord?id=CVE-2021-44228
- www.debian.org/security/2021/dsa-5022
- www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html
- www.kb.cert.org/vuls/id/930724
- www.oracle.com/security-alerts/alert-cve-2021-44228.html
- www.oracle.com/security-alerts/cpuapr2022.html
- www.oracle.com/security-alerts/cpujan2022.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.