CVE-2026-30923
libModSecurity3: ModSecurity: ModSecurity: Denial of Service via crafted query string parameter in t:hexDecode transformation
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · May 6, 2026
Updated · July 7, 2026
Description
A flaw was found in libModSecurity3, a component of the ModSecurity web application firewall (WAF). An attacker can exploit a segmentation fault by sending a specially crafted query string parameter containing a single character, which is then processed by a rule using the t:hexDecode transformation. This can cause worker processes to crash, leading to a denial of service (DoS) for the affected system.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-1287 · Improper Validation of Specified Type of Input