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Known exploited vulnerability

CVE-2021-45046

criticalCVSS 3.1 9.0In CISA KEVRansomwareEPSS 100%Published · Apache Software Foundation

The short answer

CVE-2021-45046 affects Apache Software Foundation Apache Log4j and is rated critical (CVSS 9.0). CISA added it to the Known Exploited Vulnerabilities catalog on 2023-05-01: attackers are using it, so patch it first. Fixed versions are published for log4j-core (2.16.0, 2.12.2, 2.3.1) and pax-logging-log4j2 (1.9.2, 1.10.8, 1.11.11).

What it is

It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.

Weakness: CWE-917.

Severity

9.0 critical

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploited (CISA KEV)

Yes, since May 1, 2023

Federal due date May 22, 2023

EPSS, next 30 days

100%

Higher than 100% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

Apply updates per vendor instructions.

Affected packages and fixed versions

PackageEcosystemFixed inAdvisory
org.apache.logging.log4j:log4j-coreMaven2.16.0, 2.12.2, 2.3.1GHSA-7rjr-3q55-vv33
org.ops4j.pax.logging:pax-logging-log4j2Maven1.9.2, 1.10.8, 1.11.11, 2.0.12GHSA-7rjr-3q55-vv33

Is it in your code? Drop your lockfile into the free vulnerability check, or let vulnerability watch check your repository every day and open the upgrade as a pull request.

Affected products

Apache Log4j. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2021-45046 being exploited?

Yes. CISA added CVE-2021-45046 to its Known Exploited Vulnerabilities catalog on 2023-05-01, with a federal remediation due date of 2023-05-22. CISA lists it as used in ransomware campaigns.

How do I fix CVE-2021-45046?

Upgrade to a fixed version: org.apache.logging.log4j:log4j-core (Maven) 2.16.0 or 2.12.2 or 2.3.1; org.ops4j.pax.logging:pax-logging-log4j2 (Maven) 1.9.2 or 1.10.8 or 1.11.11 or 2.0.12. CISA's required action: Apply updates per vendor instructions.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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