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CVE-2025-47947 is a denial-of-service vulnerability in ModSecurity affecting versions up to and including 2.9.8. The issue occurs in a specific processing path when a request payload uses the application/json content type and at least one configured rule invokes the sanitiseMatchedBytes action. Under that condition, crafted input can trigger abnormal processing that causes the web application firewall engine to fail in a way that results in service disruption. The vulnerability is limited to this special case and is associated with ModSecurity’s handling of JSON request bodies in conjunction with sanitization of matched bytes.
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sanitiseMatchedBytes action for JSON request processing if operationally feasible, but this is not stated by the source as an official workaround and may reduce security coverage.Patch, then assume compromise.
1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This two-file repository provides a proof-of-concept operational DoS payload for CVE-2025-47947 affecting ModSecurity v2/mod_security2 through version 2.9.8. README.md documents the vulnerable configuration, trigger rule, expected memory behavior, and mitigation version, while payload.txt is the executable Bash payload with embedded Python. The payload creates an 8,000-property JSON document and continually sends it to a locally configured HTTP target. Under the documented rule conditions, each matching JSON variable can cause repeated insertion of parsed variables into ModSecurity's sanitize table, producing quadratic memory growth in an Apache worker and potentially resulting in OOM kills and availability loss. It is not part of a known exploit framework and contains no remote shell, persistence, credential theft, or data-exfiltration capability.
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
6 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.
No news coverage yet. Advisories and community discussion only.
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.