CVE-2025-48866 ModSecurity has possible DoS vulnerability in sanitiseArg action
Attackers can cause denial of service in ModSecurity by exploiting the sanitiseArg action to add excessive arguments.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-48866?
CVE-2025-48866 is a high-severity denial of service vulnerability in owasp-modsecurity ModSecurity, published on 2 Jun 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 prior to 2.9.10 contain a denial of service vulnerability similar to GHSA-859r-vvv8-rm8r/CVE-2025-47947. The `sanitiseArg` (and `sanitizeArg` - this is the same action but an alias) is vulnerable to adding an excessive number of arguments, thereby leading to denial of service. Version 2.9.10 fixes the issue. As a workaround, avoid using rules that contain the `sanitiseArg` (or `sanitizeArg`) action.
Weakness: CWE-1050
Which versions are affected by CVE-2025-48866?
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 | 2.9.10 |
Linux distribution packages (21)
mod_security Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6.1 |
mod_security-debuginfo Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6.1 |
mod_security-debugsource Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6.1 |
mod_security-mlogc Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6.1 |
mod_security-mlogc-debuginfo Red Hat:enterprise_linux:9::appstream | All versions | 0:2.9.6-2.el9_6.1 |
mod_security Red Hat:rhel_e4s:9.0::appstream | All versions | 0:2.9.3-12.el9_0.2 |
mod_security-debuginfo Red Hat:rhel_e4s:9.0::appstream | All versions | 0:2.9.3-12.el9_0.2 |
mod_security-debugsource Red Hat:rhel_e4s:9.0::appstream | All versions | 0:2.9.3-12.el9_0.2 |
mod_security-mlogc Red Hat:rhel_e4s:9.0::appstream | All versions | 0:2.9.3-12.el9_0.2 |
mod_security-mlogc-debuginfo Red Hat:rhel_e4s:9.0::appstream | All versions | 0:2.9.3-12.el9_0.2 |
mod_security Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.9.6-1.el9_2.2 |
mod_security-debuginfo Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.9.6-1.el9_2.2 |
mod_security-debugsource Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.9.6-1.el9_2.2 |
mod_security-mlogc Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.9.6-1.el9_2.2 |
mod_security-mlogc-debuginfo Red Hat:rhel_e4s:9.2::appstream | All versions | 0:2.9.6-1.el9_2.2 |
mod_security Red Hat:rhel_eus:9.4::appstream | All versions | 0:2.9.6-1.el9_4.2 |
mod_security-debuginfo Red Hat:rhel_eus:9.4::appstream | All versions | 0:2.9.6-1.el9_4.2 |
mod_security-debugsource Red Hat:rhel_eus:9.4::appstream | All versions | 0:2.9.6-1.el9_4.2 |
mod_security-mlogc Red Hat:rhel_eus:9.4::appstream | All versions | 0:2.9.6-1.el9_4.2 |
mod_security-mlogc-debuginfo Red Hat:rhel_eus:9.4::appstream | All versions | 0:2.9.6-1.el9_4.2 |
mod_security Rocky Linux:9 | All versions | 0:2.9.6-2.el9_6.1 |
Products include Owasp Modsecurity.
How do I fix CVE-2025-48866?
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-2025-48866 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-48866 exists.
Other vulnerabilities in owasp-modsecurity ModSecurity
- CVE-2026-52747 Security feature bypass in ModSecurity
- CVE-2024-1019 WAF bypass of the ModSecurity v3 release line
- CVE-2026-42268 ModSecurity: Unsigned integer underflow in @verifySSN / @verifyCPF / @verifySVNR operators
- CVE-2026-30923 libModSecurity3 denial of service via segfault when using t:hexDecode on single-character query strings
- CVE-2023-38285 Trustwave ModSecurity 3.x before 3.0.10 has Inefficient Algorithmic Complexity.
Sources
Also known as AZL-62229, AZL-62231, BIT-modsecurity-2025-48866, BIT-modsecurity2-2025-48866, DEBIAN-CVE-2025-48866, DLA-4212-1 and 7 more.