UBUNTU-CVE-2026-73253

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Source

https://ubuntu.com/security/CVE-2026-73253

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73253.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-73253

Upstream

CVE-2026-73253

Published

2026-08-20T18:16:00Z

Modified

2026-10-17T13:01:02Z

Severity

9.1 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N CVSS Calculator
9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Ubuntu - medium

Summary

[none]

Details

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.

References

Affected packages

Ubuntu:26.10 / mongoose

Package

Name: mongoose
Purl: pkg:deb/ubuntu/mongoose?arch=source&distro=stonking

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Affected versions

7.*

7.21+ds-1

7.21+ds-2

7.22+ds-1

7.23+ds-1

Ecosystem specific

{
    "binaries":  [
        {
            "binary_name":  "mongoose-webserver-source",
            "binary_version":  "7.23+ds-1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73253.json"