Exploited CVEs / Apache / CVE-2021-45046
CVE-2021-45046
Apache Log4j2 Deserialization of Untrusted Data Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2023-05-22 (that deadline has passed); treat that date as the outer bound for your own environment. Check the vendor security advisory for the fix.
Actively exploited Apache Log4j2 vulnerability, Critical severity, CVSS 9.0. Added to the CISA KEV catalog 2023-05-01.
Risk summary
Updated July 28, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2021-45046
This is the incomplete-fix follow-up to Log4Shell: Apache Log4j2's initial patch for CVE-2021-44228 left the Thread Context Lookup pattern exploitable for remote code execution in certain non-default configurations, Critical Severity at CVSS 9.0, EPSS 100%, with confirmed ransomware use (KEV, 2023-05-01). Organizations that patched once when the original flaw broke and never revisited it may still be running the intermediate vulnerable version. Log4j's presence buried inside vendor appliances and Java apps keeps discovery hard years later.
Do this: Rescan your environment for Log4j2 versions fixed only against the original flaw and upgrade them fully, including embedded copies in appliances.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2021-45046
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2021-45046
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2023-05-22 (past due).
Apply updates per vendor instructions.
Official fix for CVE-2021-45046
Check the vendor's security advisory channel for the patched Log4j2 versions and workarounds.
Common questions about CVE-2021-45046
Is CVE-2021-45046 actively exploited?
Yes. CVE-2021-45046 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2023-05-01, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 100%. CISA also reports it is known to be used in ransomware campaigns.
What is the CISA deadline and required action for CVE-2021-45046?
CISA set the federal (BOD 22-01) remediation due date at 2023-05-22, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.
What fixes CVE-2021-45046?
Check the vendor's security advisory for the patched Log4j2 versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2021-45046?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2021-45046's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
More exploited Apache CVEs
The newest Apache entries on the CISA KEV catalog:
All Apache exploited CVEs on one page: Apache vulnerabilities actively exploited.
Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.
