CVE-2026-52747
ModSecurity multipart parser drops line breaks, enabling WAF rule evasion
Is CVE-2026-52747 being exploited?
Not confirmed. CVE-2026-52747 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.48% probability of exploitation in the next 30 days.
How severe is CVE-2026-52747?
CVE-2026-52747 is rated High with a CVSS score of 8.6. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-52747?
Yes. A fix has been recorded for CVE-2026-52747. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-52747 affect?
CVE-2026-52747 affects ModSecurity libmodsecurity < 3.0.16, Deployments on Apache, Nginx, IIS using affected parser. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-52747?
Upgrade ModSecurity to 3.0.16 immediately and review WAF rules and logs.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attackers can craft multipart/form-data with embedded line breaks to bypass ARGS/ARGS_POST inspection, allowing malicious payloads to reach backends and potentially enable RCE or data theft.
Patch when possible
- affected< 3.0.16
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.