CVE-2026-34481 (GCVE-0-2026-34481)
Vulnerability from cvelistv5 – Published: 2026-04-10 15:43 – Updated: 2026-04-10 17:41
VLAI?
Title
Apache Log4j JSON Template Layout: Improper serialization of non-finite floating-point values in JsonTemplateLayout
Summary
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 containing an attacker-controlled floating-point value.
Users are advised to upgrade to Apache Log4j JSON Template Layout 2.25.4, which corrects this issue.
Severity ?
CWE
- CWE-116 - Improper Encoding or Escaping of Output
Assigner
References
| URL | Tags | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Apache Software Foundation | Apache Log4j JSON Template Layout |
Affected:
2.14.0 , < 2.25.4
(maven)
Affected: 3.0.0-alpha1 , ≤ 3.0.0-beta3 (maven) cpe:2.3:a:apache:log4j_layout_template_json:*:*:*:*:*:*:*:* |
Credits
Ap4sh (Samy Medjahed) and Ethicxz (Eliott Laurie)
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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