Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-73253

CVE-2026-73253CRITICAL

cesanta mongoose — Mongoose: TLS Hostname Verification Bypass via Overly Permissive Wildcard Matching

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   P   N   N   H   H   N    9.1   .0034   25.6     —

AFFECTED
  Product   Versions  Fixed
  mongoose  < 7.22 –  —

TIMELINE
  Aug 11  Reserved by GitHub_M
  Aug 20  Published (CNA: GitHub_M)
  Sep 29  EXPLOIT PUBLISHED — CVE-2026-73253 (cesanta mongoose). Public exploit reference added.

CWE-295 · CNA: GitHub_M · CVSS v4.0 · 4 references · NVD status: Analyzed

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
August 11, 2026	Reserved	Reserved by GitHub_M
August 20, 2026	Published	Published (CNA: GitHub_M)
September 29, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-73253 (cesanta mongoose). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
cesanta	mongoose	—	< 7.22	—

Weaknesses

CWE-295

References (4)

https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71 [Patch]
https://github.com/cesanta/mongoose/pull/3611 [Issue Tracking, Patch]
https://github.com/cesanta/mongoose/releases/tag/7.22 [Release Notes]
https://github.com/cesanta/mongoose/security/advisories/GHSA-jp6g-796f-39vp [Exploit, Vendor Advisory]

Authoritative record: CVE-2026-73253 at cve.org

Vendors: cesanta

Weaknesses: CWE-295

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-73253 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Saturday, October 3, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.