CVE-2026-30923

Name: CVE-2026-30923
Creator: NVD / NIST
Published: 2026-05-05T19:16:21.567+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.2/10EPSS 0.43%

Last modified Jun 17, 2026

CVE-2026-30923 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Libmodsecurity is one component of the ModSecurity v3 project. EPSS estimates a 0.43% chance of exploitation in the next 30 days.

Description

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Libmodsecurity is one component of the ModSecurity v3 project. A segmentation fault occurs when a rule using the t:hexDecode transformation inspects a query string parameter containing a single character. An attacker can exploit this to crash worker processes, causing a denial of service. Service resumes once the attack stops as worker processes recover from the segfault. All versions before 3.0.15 of libModSecurity3 are affected. This has been patched in version 3.0.15.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 4.0

8.2/10

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.43%

34.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-125

Affected Software

Vendor	Product	Versions
Owasp	Modsecurity	< 3.0.15

References

https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.15Patch, Product
https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qrjc-3jpc-3h2gExploit, Vendor Advisory
https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qrjc-3jpc-3h2gExploit, Vendor Advisory

Timeline

Published: May 5, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-30923?

How severe is CVE-2026-30923?

CVE-2026-30923 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.43% probability of exploitation in the next 30 days.

How do I fix CVE-2026-30923?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-30923?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST