Bug 2567914 (CVE-2026-61813)

Summary:	CVE-2026-61813 mod_security: modsecurity: ModSecurity: Weak TLS certificate validation via improper hostname verification
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	csutherl, jclere, pjindal, plodge, rhel-process-autobot, szappis, vchlup, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in ModSecurity. An attacker positioned in the communication path can bypass peer identity verification due to an improper Transport Layer Security (TLS) hostname validation setting in the internal HTTPS client. This issue allows the attacker to present a certificate issued for an unintended host, potentially enabling them to intercept or tamper with encrypted traffic.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-11-05 22:36:00 UTC

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 2.9.15 and 3.0.17, the HttpsClient::download function in src/utils/https_client.cc sets libcurl CURLOPT_SSL_VERIFYHOST to 1 instead of the strict value 2L. Under adversary-in-the-middle and TLS interception conditions, this non-strict setting may weaken TLS peer identity validation and increase the risk of accepting a certificate for an unintended host. End-to-end exploitation is non-trivial in typical environments. This issue is fixed in versions 2.9.15 and 3.0.17.