Vulnerabilities/Apache/CVE-2021-45046

CVE-2021-45046: Apache Log4j2 Deserialization of Untrusted Data Vulnerability

CISA KEV entry · Last checked 30 Oct 2026, 12:10 UTC

Exploitation confirmedRansomware use knownFix: Unknown

CVSS 3.1 · NVD9.0Critical
EPSS100.0%100th percentile · 29 Oct 2026
CISA KEVListedAdded 1 May 2023

Apache Log4j2 contains a deserialization of untrusted data vulnerability due to the incomplete fix of CVE-2021-44228, where the Thread Context Lookup Pattern is vulnerable to remote code execution in certain non-default configurations.

Recommended action

Apply updates per vendor instructions.

CISA due date 22 May 2023 · CWE-917

Vendor advisory ↗CISA KEV entry ↗

Am I affected?

ProductAffected versionsFixed in
Apache Log4jApache Log4j2 to before 2.16.0Unknown

No source states a fixed version. Check the vendor advisory below.

Before you patch

Restart

See vendor guidance.

Known issues

Check release notes.

Verification

Confirm installed version.

Timeline

  • 1 May 2023 · Added to CISA KEV
  • 22 May 2023 · CISA due date

References

Sources checked
CISA KEV30 Oct 2026, 12:10 UTC
CVE List v530 Oct 2026, 12:10 UTC
NVD30 Oct 2026, 12:10 UTC
FIRST EPSS30 Oct 2026, 12:11 UTC

Data from CISA, MITRE, NVD and FIRST. Sources and licences.