CVE-2026-34481
7.5 · HIGHOverview
CVE-2026-34481 is a high-severity vulnerability affecting apache log4j. It was published on April 10, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Apache Log4j's JsonTemplateLayout https://logging.apache.org/log4j/2.x/manual/json-template-layout.html , in versions up to and including 2.25.3, produces invalid JSON output when log events contain non-finite floating-point values (NaN, Infinity, or -Infinity), which are prohibited by RFC 8259. This may cause downstream log processing systems to reject or fail to index affected records.
An attacker can exploit this issue only if both of the following conditions are met:
* The application uses JsonTemplateLayout.
* The application logs a MapMessage, or logs an object directly (e.g., via Logger.info(Object), which wraps it in an ObjectMessage), where the message contains an attacker-controlled floating-point value.
Users are advised to upgrade to Apache Log4j JSON Template Layout 2.25.4, which corrects this issue.
Note: The fix released in version 2.25.4 did not cover all affected code paths. CVE-2026-49844 was assigned to the remaining issue, which concerns the MapMessage.a
Remediation
Check the references section for vendor advisories and patches from apache. Update log4j to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| apache | log4j | >= 2.14.0, < 2.25.4 | Affected |
References
Frequently Asked Questions
What is CVE-2026-34481?
CVE-2026-34481 is a high-severity vulnerability affecting apache log4j. It was published on April 10, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-34481?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-34481?
Check the references section for vendor advisories and patches from apache. Update log4j to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-34481?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-34481 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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