CVE-2021-44228
Log4Shell
Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.
- CVSS
- 10.0Criticalscored by CISA
- Exploited in the wild
- Yes, in CISA KEV since 10 Dec 2021CISA deadline for US federal agencies: 24 Dec 2021known use in ransomware campaignspublic exploit code
- EPSS
- > 99.9%chance of exploitation in the next 30 daystop 0.1% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 10 Dec 2021analysed here 12 Nov 2026
Do first. For all affected software assets for which updates exist, the only acceptable remediation actions are: 1) Apply updates; OR 2) remove affected assets from agency networks. Temporary mitigations using one of the measures provided at https://www.cisa.gov/uscert/ed-22-02-apache-log4j-recommended-mitigation-measures are only acceptable until updates are available. (CISA's required action for this KEV entry)
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Apache Software Foundation Apache Log4j2 | >= 2.0-beta9 and < log4j-core*Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- siemens:6bk1602-0aa12-0tp0_firmware
- siemens:6bk1602-0aa22-0tp0_firmware
- siemens:6bk1602-0aa32-0tp0_firmware
- siemens:6bk1602-0aa42-0tp0_firmware
- siemens:6bk1602-0aa52-0tp0_firmware
- apache:log4j
- siemens:sppa-t3000_ses3000_firmware
- siemens:capital
- siemens:comos
- siemens:desigo_cc_advanced_reports
- siemens:desigo_cc_info_center
- siemens:e-car_operation_center
- siemens:energy_engage
- siemens:energyip
- siemens:energyip_prepay
- siemens:gma-manager
- siemens:head-end_system_universal_device_integration_system
- siemens:industrial_edge_management
- siemens:industrial_edge_management_hub
- siemens:logo\!_soft_comfort
- siemens:mendix
- siemens:mindsphere
- siemens:navigator
- siemens:nx
- siemens:opcenter_intelligence
- siemens:operation_scheduler
- siemens:sentron_powermanager
- siemens:siguard_dsa
- siemens:sipass_integrated
- siemens:siveillance_command
Fix and mitigation
WAF and other mitigations
Can a WAF block it? Partly. AWS WAF, Azure WAF and Google Cloud Armor publish WAF rules written for this CVE. Such rules block the known exploit requests and buy time, but attackers can change the request to get past them, so they do not replace the patch.
AWS WAF · 2 rules · since 10 Dec 2021
- BadAuthToken_COOKIE_AUTHORIZATION · Known bad inputs
- Log4JRCE · Known bad inputs
Google Cloud Armor · 2 rules
Also consider: patch · enable the vendor rule in block mode · rate limit · CDN · allow-list classes
Based on WAF vendor rules published for this CVE. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 10 Dec 2021. Known use in ransomware campaigns.
- CISA due date
- 24 Dec 2021, the remediation deadline for US federal agencies
- CISA required action
- For all affected software assets for which updates exist, the only acceptable remediation actions are: 1) Apply updates; OR 2) remove affected assets from agency networks. Temporary mitigations using one of the measures provided at https://www.cisa.gov/uscert/ed-22-02-apache-log4j-recommended-mitigation-measures are only acceptable until updates are available.
- Public exploit code
- Yes: 3 on Exploit-DB · 5 Metasploit modules · 507 GitHub proofs of concept · 1 Nuclei template
- CISA SSVC
- exploitation active, automatable yes, technical impact totalAssessed by CISA 4 Feb 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Exploit-DB
- AD Manager Plus 7122 - Remote Code Execution (RCE)remote, 1 Apr 2023
- Apache Log4j 2 - Remote Code Execution (RCE)remote, 14 Dec 2021
- Apache Log4j2 2.14.1 - Information Disclosureremote, 14 Dec 2021
Metasploit
- exploit/linux/http/mobileiron_core_log4shellexploit, rank excellent
- exploit/multi/http/log4shell_header_injectionexploit, rank excellent
- exploit/multi/http/ubiquiti_unifi_log4shellexploit, rank excellent
- exploit/multi/http/vmware_vcenter_log4shellexploit, rank excellent
Nuclei
- Apache Log4j2 Remote Code Injectiondetection template, critical
GitHub proofs of concept
- fullhunt/log4j-scan3,425 stars
- kozmer/log4j-shell-poc1,843 stars
- christophetd/log4shell-vulnerable-app1,144 stars
- Puliczek/CVE-2021-44228-PoC-log4j-bypass-words952 stars
and 503 more repositories
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
Timeline
- 9 Dec 2021First public exploit or proof of concept
- 10 Dec 2021Added to CISA KEV (exploited in the wild)1 day later
- 10 Dec 2021Publishedsame day later
- 24 Dec 2021CISA remediation due date (US federal agencies)14 days later
- 4 Feb 2025CISA SSVC assessment: exploitation active1,139 days (about 3 years) later
- 21 Oct 2025CVE record last updated259 days (about 9 months) later
- 12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | NetworkReachable over the internet or any routable network. | Reachable over the internet or any routable network. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | ChangedImpact crosses a security boundary into other components. | Impact crosses a security boundary into other components. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2021-44228 being exploited?
Yes. CVE-2021-44228 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2021-44228?
CVE-2021-44228 is rated Critical with a CVSS score of 10.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2021-44228?
Yes. A fix has been recorded for CVE-2021-44228. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2021-44228 affect?
CVE-2021-44228 affects siemens:6bk1602-0aa12-0tp0_firmware, siemens:6bk1602-0aa22-0tp0_firmware, siemens:6bk1602-0aa32-0tp0_firmware, siemens:6bk1602-0aa42-0tp0_firmware, and 26 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
50 references in the CVE record, grouped by the tags the record gives them.
Advisories (6)
- tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd
- debian.org /security/2021/dsa-5020
- lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/VU57UJDCFIASIO
- msrc-blog.microsoft.com /2021/12/11/microsofts-response-to-cve-2021-44228-apache-log4j2/
- kb.cert.org /vuls/id/930724
- lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/M5CSVUNV4HWZZX
Other links (44)
- logging.apache.org /log4j/2.x/security.html
- openwall.com /lists/oss-security/2021/12/10/1
- openwall.com /lists/oss-security/2021/12/10/2
- openwall.com /lists/oss-security/2021/12/10/3
- security.netapp.com /advisory/ntap-20211210-0007/
- packetstormsecurity.com /files/165225/Apache-Log4j2-2.14.1-Remote-Code-Execution.html
Show 38 more
- psirt.global.sonicwall.com /vuln-detail/SNWLID-2021-0032
- oracle.com /security-alerts/alert-cve-2021-44228.html
- lists.debian.org /debian-lts-announce/2021/12/msg00007.html
- openwall.com /lists/oss-security/2021/12/13/2
- openwall.com /lists/oss-security/2021/12/13/1
- openwall.com /lists/oss-security/2021/12/14/4
- twitter.com /kurtseifried/status/1469345530182455296
- cert-portal.siemens.com /productcert/pdf/ssa-661247.pdf
- packetstormsecurity.com /files/165260/VMware-Security-Advisory-2021-0028.html
- packetstormsecurity.com /files/165270/Apache-Log4j2-2.14.1-Remote-Code-Execution.html
- packetstormsecurity.com /files/165261/Apache-Log4j2-2.14.1-Information-Disclosure.html
- intel.com /content/www/us/en/security-center/advisory/intel-sa-00646.html
- openwall.com /lists/oss-security/2021/12/15/3
- packetstormsecurity.com /files/165282/Log4j-Payload-Generator.html
- packetstormsecurity.com /files/165281/Log4j2-Log4Shell-Regexes.html
- packetstormsecurity.com /files/165307/Log4j-Remote-Code-Execution-Word-Bypassing.html
- packetstormsecurity.com /files/165311/log4j-scan-Extensive-Scanner.html
- packetstormsecurity.com /files/165306/L4sh-Log4j-Remote-Code-Execution.html
- cert-portal.siemens.com /productcert/pdf/ssa-714170.pdf
- packetstormsecurity.com /files/165371/VMware-Security-Advisory-2021-0028.4.html
- cert-portal.siemens.com /productcert/pdf/ssa-397453.pdf
- cert-portal.siemens.com /productcert/pdf/ssa-479842.pdf
- oracle.com /security-alerts/cpujan2022.html
- packetstormsecurity.com /files/165532/Log4Shell-HTTP-Header-Injection.html
- github.com /cisagov/log4j-affected-db/blob/develop/SOFTWARE-LIST.md
- packetstormsecurity.com /files/165642/VMware-vCenter-Server-Unauthenticated-Log4Shell-JNDI-Injection-Rem
- packetstormsecurity.com /files/165673/UniFi-Network-Application-Unauthenticated-Log4Shell-Remote-Code-Ex
- seclists.org /fulldisclosure/2022/Mar/23
- bentley.com /en/common-vulnerability-exposure/be-2022-0001
- github.com /cisagov/log4j-affected-db
- support.apple.com /kb/HT213189
- oracle.com /security-alerts/cpuapr2022.html
- github.com /nu11secur1ty/CVE-mitre/tree/main/CVE-2021-44228
- nu11secur1ty.com /2021/12/cve-2021-44228.html
- seclists.org /fulldisclosure/2022/Jul/11
- packetstormsecurity.com /files/167794/Open-Xchange-App-Suite-7.10.x-Cross-Site-Scripting-Command-Injecti
- packetstormsecurity.com /files/167917/MobileIron-Log4Shell-Remote-Command-Execution.html
- seclists.org /fulldisclosure/2022/Dec/2
Also tracked as GHSA-jfh8-c2jp-5v3q (OSV).
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Exploit-DB: published exploits
- Metasploit Framework: exploit and scanner modules
- Nuclei templates: detection templates
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
- OSV: advisory aliases and downstream package versions
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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