CVE-2021-45046: Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack
Noroxi assessment
Priority: Now (action score 96/100)
- CISA has confirmed exploitation in the wild (May 1, 2023); it is known to be used in ransomware campaigns. Remediation deadline for US federal agencies: May 22, 2023.
- A ready-made attack module is public (Metasploit, Nuclei); exploiting it takes no special expertise.
- 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-log4j2 (Debian:10) 2.16.0-1~deb10u1; apache-log4j2 (Debian:11) 2.16.0-1~deb11u1; apache-log4j2 (Debian:12) 2.16.0-1.
- Mentioned 6 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Patch today or shut off access. Upgrade to apache-log4j2 (Debian:10) 2.16.0-1~deb10u1; apache-log4j2 (Debian:11) 2.16.0-1~deb11u1; apache-log4j2 (Debian:12) 2.16.0-1 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 · CISA KEV · FIRST EPSS
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
- 99.9% · 99th percentile
- CWE
- CWE-917
Report tools
Action score
96
Patch today or shut off access.
- CVSS
- 36 / 40 · 9.0 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 30 / 30 · 99.9%
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 US federal agencies: May 22, 2023.
Known to be used in ransomware campaigns.
Get told when this record changes
- In CISA KEV: exploitation in the wild confirmed
- Weaponized exploit exists
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi 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.
We use this product, ask for helpAffected 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.
| 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
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
Affected versions · NVD (20)
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
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 | from 2.4.0 · before 2.12.2 | 2.12.2 |
| Maven | org.apache.logging.log4j:log4j-core | before 2.3.1 | 2.3.1 |
| 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 2.16.0-4.10.1 | 2.16.0-4.10.1 |
| openSUSE:Leap 15.3 | log4j | before 2.13.0-4.6.1 | 2.13.0-4.6.1 |
| 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 |
+66
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…66This 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…60This 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 1.254Plan
- Later →CVE-2021-45105Dec 18, 2021 · Apache Log4j2 does not always protect from infinite recursion in lookup evaluation53Plan
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.apache.logging.log4j:log4j-core | 2.3.1 | 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 |
|---|---|---|
| Proof-of-concept repository on GitHub | 11 repositories | 2021-12-15 → 2025-07-23 |
| 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 | — |
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
- TodayNov 14, 2026+1795 d
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-22-0436 · Jun 20, 2022(IBM Güvenlik Bildirimi)
- TR-22-0435 · Jun 17, 2022(RedHat Güvenlik Güncellemesi)
- TR-22-0248 · Mar 24, 2022(IBM Güvenlik Zafiyeti)
- TR-22-0151 · Feb 17, 2022(IBM Güvenlik Bildirimi)
- TR-22-0074 · Jan 21, 2022(VMware Güvenlik Güncellemesi)
- TR-22-0052 · Jan 17, 2022(IBM Güvenlik Bülteni)
Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate.
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.
Change log (1)
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- 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.