SB20260629135 - Multiple vulnerabilities in ModSecurity

Description

This security bulletin contains information about 2 vulnerabilities.

1) Use of sizeof() on a Pointer Type (CVE-ID: CVE-2026-52761)

CWE-ID: CWE-467 - Use of sizeof() on a Pointer Type

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to bypass security rules.

The vulnerability exists due to use of sizeof() on a pointer type in the t:utf8toUnicode transformation when processing UTF-8 input on i386 architecture. A remote attacker can send specially crafted input to bypass security rules.

Only i386 architecture is affected.

2) Incorrect Behavior Order: Validate Before Canonicalize (CVE-ID: CVE-2026-52747)

CWE-ID: CWE-180 - Incorrect Behavior Order: Validate Before Canonicalize

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber

The vulnerability allows a remote attacker to bypass request-body inspection.

The vulnerability exists due to incorrect behavior order: validate before canonicalize in the libmodsecurity multipart/form-data request body parser when processing non-file multipart form-field values containing embedded line breaks. A remote attacker can send a specially crafted multipart/form-data request to bypass request-body inspection.

The issue affects values exported to ARGS and ARGS_POST, while built-in multipart strict-validation variables can remain clear.

Remediation

Install update from vendor's website.

References

• https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qjgm-7gp4-f8qq
• https://github.com/owasp-modsecurity/ModSecurity/blame/v3.0.15/src/actions/transformations/utf8_to_unicode.cc#L136-L138
• https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2f5r-7p88