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CVE-2026-30923

Owasp Modsecurity out-of-bounds read

7.5 HIGHPublic exploitEPSS 0.52%
  1. Published5 May 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Owasp Modsecurity< 3.0.15

Remediation

Fixed in
Owasp Modsecurity≥ 3.0.15

References

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Frequently asked

Is CVE-2026-30923 being actively exploited?

CVE-2026-30923 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.52%.

How severe is CVE-2026-30923?

CVE-2026-30923 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.52% probability of exploitation.

Which products are affected by CVE-2026-30923?

Affected products include Owasp Modsecurity.

How do I fix CVE-2026-30923?

Upgrade affected software to a fixed version, for example Owasp Modsecurity 3.0.15 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-30923 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.