Threats / Apache / CVE-2021-44228
CVE-2021-44228
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Apache Log4j2 vulnerability
Apache Log4j2 does not adequately validate JNDI endpoints, permitting remote code execution through attacker-controlled JNDI references.
Verdict
Today item, not a backlog item.
A remote code execution vulnerability in Log4j2's JNDI handling allows unauthenticated attackers to execute arbitrary code on affected systems. The vulnerability has been actively exploited in ransomware campaigns and poses critical risk to internet-facing applications.
CISA KEV Yes · 2021-12-103Ransomware use Flagged3EPSS 0.99999 (verify live)4Exploit Weaponized · public PoC5
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
1195 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-12-10), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.99999 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Apache, Log4j2. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation, CWE-400 Uncontrolled Resource Consumption, CWE-502 Deserialization of Untrusted Data — weakness family: Resource / availability, Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
WeaknessCWE-20 · Improper Input ValidationCWE-400 · Uncontrolled Resource ConsumptionCWE-502 · Deserialization of Untrusted DataResource / availability, Injection
02
Who’s exploiting it?
— attribution turns risk into urgencyAPT40 State-sponsored (PRC)
The CISA-led joint advisory AA24-190A names APT40 (tracked in ATT&CK as Leviathan) as a PRC Ministry of State Security group that rapidly weaponizes newly public vulnerabilities, naming the ProxyShell Exchange chain, Log4Shell, and Atlassian Confluence CVEs alongside the group.14
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious log message containing a JNDI reference pointing to an attacker-controlled endpoint.
Business
An attacker gains the ability to execute code on production systems running vulnerable Log4j2 versions.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I trigger the vulnerable application to process my crafted log input, causing it to resolve the JNDI reference without validation.
Business
Ransomware operators deploy payloads at scale, compromising thousands of systems across critical infrastructure and enterprises.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish command execution on the target system through the resolved JNDI endpoint.
Business
Organizations face data exfiltration, system encryption, operational disruption, and significant financial and reputational damage.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by apacheCNA
Credited with finding itThis issue was discovered by Chen Zhaojun of Alibaba Cloud Security Team.unspecified