SB2026042914 - Multiple vulnerabilities in ModSecurity

Description

This security bulletin contains information about 2 vulnerabilities.

1) Integer underflow (CVE-ID: CVE-2026-42268)

CWE-ID: CWE-191 - Integer underflow

CVSSv4: 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

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.

2) Out-of-bounds read (CVE-ID: CVE-2026-30923)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 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

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to out-of-bounds read in the t:hexDecode transformation when processing query strings containing a single character under a rule that inspects query string arguments. A remote attacker can send a specially crafted request to cause a denial of service.

Only configurations that use the t:hexDecode transformation on query string inspection are vulnerable.

Remediation

Install update from vendor's website.

References

• https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-vwr3-7x7g-7p9w
• https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qrjc-3jpc-3h2g