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Apache Log4j JsonTemplateLayout through version 2.25.3 improperly serializes non-finite IEEE 754 floating-point values. When a logged MapMessage, or an object logged as an ObjectMessage, contains NaN, Infinity, or -Infinity, the layout emits these values as bare tokens. Because RFC 8259 prohibits these tokens in JSON, the resulting log event is invalid JSON. This defect can cause consumers of structured logs to reject, fail to parse, or fail to index affected records.
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No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
22 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An earlier Apache Log4j API vulnerability whose fix did not cover every MapMessage JSON serialization code path. The remaining non-finite floating-point serialization defect is identified as CVE-2026-49844. The reference does not separately describe the earlier vulnerability's full scope, affected versions, or exploitation status.
Denial of service in Log4j JsonTemplateLayout through invalid JSON output.
Apache Log4j JsonTemplateLayout denial of service caused by invalid JSON output.
Previously fixed Apache Log4j issue referenced only as background for CVE-2026-49844.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.