SEPTEMBER 17, 2026
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Case File

CVE-2026-73253

CRITICAL · CVSS 9.1 EPSS 0.21% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-20 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

An on-path network attacker can exploit a vulnerability in Mongoose prior to version 7.22 to impersonate subdomains using a wildcard certificate, allowing them to bypass hostname verification and intercept TLS traffic. This critical flaw poses a significant risk to any applications utilizing Mongoose for secure communications, particularly those handling sensitive data. Organizations using affected versions should prioritize upgrading to version 7.22 to mitigate the risk of interception and data compromise.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-73253
Severity
CRITICAL
CVSS
9.1
EPSS
0.21%

Original NVD Description

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.