Bug 2538668

Summary: CVE-2026-73253 mongoose: Mongoose: TLS Hostname Verification Bypass via Overly Permissive Wildcard Matching [fedora-all]
Product: [Fedora] Fedora Reporter: aedmond
Component: mongooseAssignee: Orphan Owner <extras-orphan>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: urgent Docs Contact:
Priority: urgent    
Version: rawhideCC: cz172638, extras-orphan, fedora
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["daac8a45-eed0-4c0a-8243-53dfa45fbcba"]}
Fixed In Version: Doc Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2520645    

Description aedmond 2026-09-22 19:58:57 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Mongoose is an embedded web server and network library. Prior to version 7.22, an on-path network attacker with a wildcard certificate for a parent domain can impersonate deeper subdomains to a client using the built-in TLS stack. The mg_tls_verify_cert_san() and mg_tls_verify_cert_cn() functions in src/tls_builtin.c call mg_match(), whose wildcard can cross DNS label boundaries, so a pattern such as *.example.com can match foo.bar.example.com. The resulting hostname verification bypass permits interception and modification of TLS traffic. This issue is fixed in version 7.22.