Integer underflow in ModSecurity - CVE-2026-42268
Published: April 29, 2026
Vulnerability identifier: #VU128452
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-42268
CWE-ID: CWE-191
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Trustwave
Affected software:
ModSecurity
ModSecurity
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to integer underflow in @verifySSN, @verifyCPF, and @verifySVNR operators when processing empty input. A remote attacker can send a specially crafted request to cause a denial of service.
Exploitation requires a rule using one of these operators to be configured, and an uncaught std::out_of_range exception reaches std::terminate() and kills the process.
How to mitigate CVE-2026-42268
Install security update from vendor's website.