CVE-2021-45046
Log4j Incomplete-Fix RCE: stopped at runtime
Waratek RASP already blocks this exploit at runtime, inside the JVM - with no application change, no vendor patch, and no downtime.
Published December 14, 2021 · Updated March 4, 2026
The vulnerability
Remote code execution via Thread Context Map JNDI lookup
The 2.15.0 patch for Log4Shell (CVE-2021-44228) disabled the default JNDI lookup pattern but left non-default configurations exposed: when Pattern Layout uses a Context Lookup or a Thread Context Map pattern, attacker-controlled MDC input can still smuggle a JNDI lookup through and trigger remote code execution or information leakage.
Running an affected version? We can help.
Waratek RASP shields the vulnerable code in production - the exploit is blocked at runtime with no library upgrade, no redeploy, and no downtime. We can have you covered fast.
How Waratek RASP stops it
Blocked at runtime by Waratek RASP
Waratek RASP ships a patch rule that blocks exploitation at the exact point the dangerous operation is attempted, inside the JVM.
Runtime, not perimeter
Waratek RASP acts inside the JVM at the exact call that turns input into code, so obfuscated and encoded payloads are caught where a WAF misses them.
No code changes
Protection is applied as a rule at runtime. No source edits, no recompilation, no library upgrade, and no application restart required.
Zero false positives
Rules target the specific unsafe behaviour of the exploit, so legitimate traffic keeps flowing while the attack is blocked and logged.
| Mod | Rules | Enable |
|---|---|---|
| Log4j Incomplete-Fix RCE protectionCVE-2021-45046 · JNDI injection / unsafe deserialization | 1 | |
| SQL Injection protectionQuery manipulation | 4 | |
| Path Traversal protectionUnsafe file access | 3 |
Flip one toggle in the Waratek Portal. The protection deploys to every attached application, with no restart.
Common questions
Log4j Incomplete-Fix RCE FAQ
Is Log4j Incomplete-Fix RCE (CVE-2021-45046) exploitable?
CVE-2021-45046 carries a CVSS 9/10 (CRITICAL) rating and affects Apache Log4j 2 (log4j-core) 2.0-beta9 through 2.15.0 (excluding 2.12.2, 2.12.3, 2.3.1). The 2.15.0 patch for Log4Shell (CVE-2021-44228) disabled the default JNDI lookup pattern but left non-default configurations exposed: when Pattern Layout uses a Context Lookup or a Thread Context Map pattern, attacker-controlled MDC input can still smuggle a JNDI lookup through and trigger remote code execution or information leakage. It is listed in CISA's Known Exploited Vulnerabilities catalog, with known ransomware campaign use.
How does Waratek mitigate Log4j Incomplete-Fix RCE (CVE-2021-45046)?
Waratek RASP blocks exploitation of Log4j Incomplete-Fix RCE (CVE-2021-45046) inside the JVM at runtime, with no application code changes, no vendor patch and no restart.
How quickly was Log4j Incomplete-Fix RCE (CVE-2021-45046) exploited after disclosure?
A working exploit for CVE-2021-45046 appeared within 2 days of its NVD disclosure, on December 15, 2021.
Protect your apps in production
Get protected against Log4j Incomplete-Fix RCE - without code changes or redeploying
Book a call and we’ll show you how Waratek RASP shields your running applications against CVE-2021-45046 and attacks like it, and get you covered in production.