CVE-2025-47947 ModSecurity Has Possible DoS Vulnerability
Attackers can cause denial of service in ModSecurity when processing JSON payloads with specific sanitization rules, requiring a patch to mitigate.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-47947?
CVE-2025-47947 is a high-severity denial of service vulnerability in owasp-modsecurity ModSecurity, published on 21 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Versions up to and including 2.9.8 are vulnerable to denial of service in one special case (in stable released versions): when the payload's content type is `application/json`, and there is at least one rule which does a `sanitiseMatchedBytes` action. A patch is available at pull request 3389 and expected to be part of version 2.9.9. No known workarounds are available.
Weakness: CWE-1050
Which versions are affected by CVE-2025-47947?
2 open source packages ship an affected version, including modsecurity and modsecurity2. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
modsecurity Bitnami | All versions | 3.0.12 |
modsecurity2 Bitnami | All versions | 2.9.9 |
Linux distribution packages (38)
mod_security AlmaLinux:8 | All versions | 2.9.6-2.el8_10 |
mod_security-mlogc AlmaLinux:8 | All versions | 2.9.6-2.el8_10 |
mod_security AlmaLinux:9 | All versions | 2.9.6-2.el9_6 |
mod_security-mlogc AlmaLinux:9 | All versions | 2.9.6-2.el9_6 |
mod_security Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.6-2.el8_10 |
mod_security-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.6-2.el8_10 |
mod_security-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.6-2.el8_10 |
mod_security-mlogc Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.6-2.el8_10 |
mod_security-mlogc-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 0:2.9.6-2.el8_10 |
mod_security Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6 |
mod_security-debuginfo Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6 |
mod_security-debugsource Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6 |
mod_security-mlogc Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6 |
mod_security-mlogc-debuginfo Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6 |
mod_security Red Hat:rhel_aus:8.2::appstream | All versions | 0:2.9.2-8.el8_2.1 |
mod_security-debuginfo Red Hat:rhel_aus:8.2::appstream | All versions | 0:2.9.2-8.el8_2.1 |
mod_security-debugsource Red Hat:rhel_aus:8.2::appstream | All versions | 0:2.9.2-8.el8_2.1 |
mod_security-mlogc Red Hat:rhel_aus:8.2::appstream | All versions | 0:2.9.2-8.el8_2.1 |
mod_security-mlogc-debuginfo Red Hat:rhel_aus:8.2::appstream | All versions | 0:2.9.2-8.el8_2.1 |
mod_security Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.9.2-9.el8_4.1 |
mod_security-debuginfo Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.9.2-9.el8_4.1 |
mod_security-debugsource Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.9.2-9.el8_4.1 |
mod_security-mlogc Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.9.2-9.el8_4.1 |
mod_security-mlogc-debuginfo Red Hat:rhel_aus:8.4::appstream | All versions | 0:2.9.2-9.el8_4.1 |
mod_security Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security-debuginfo Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security-debugsource Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security-mlogc Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security-mlogc-debuginfo Red Hat:rhel_aus:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security Red Hat:rhel_e4s:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security-debuginfo Red Hat:rhel_e4s:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security-debugsource Red Hat:rhel_e4s:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security-mlogc Red Hat:rhel_e4s:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security-mlogc-debuginfo Red Hat:rhel_e4s:8.6::appstream | All versions | 0:2.9.2-9.el8_6.1 |
mod_security Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.9.6-1.el8_8.1 |
mod_security-debuginfo Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.9.6-1.el8_8.1 |
mod_security-debugsource Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.9.6-1.el8_8.1 |
mod_security-mlogc Red Hat:rhel_e4s:8.8::appstream | All versions | 0:2.9.6-1.el8_8.1 |
Products include Trustwave Modsecurity.
How do I fix CVE-2025-47947?
Upgrade modsecurity to 3.0.12 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-47947 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-47947 exists.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in owasp-modsecurity ModSecurity
Sources
Also known as ALSA-2025:8837, ALSA-2025:8844, AZL-62426, BIT-modsecurity-2025-47947, BIT-modsecurity2-2025-47947, CLSA-2025-1762421346 and 17 more.