UBUNTU-CVE-2026-73251

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/CVE-2026-73251
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73251.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-73251
Upstream
Published
2026-08-20T18:16:00Z
Modified
2026-10-17T13:01:01Z
Severity
  • 9.3 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/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 7.23, a network attacker can impersonate a TLS server to a Mongoose client configured with a multi-certificate CA bundle. In src/tls_builtin.c, the mg_tls_init() function stores the bundle in tls->ca_bundle_der while tls->ca_der.len remains zero, and mg_tls_recv_cert() uses tls_bundle_find() to accept a Common Name match without calling mg_tls_verify_cert_signature(). A forged self-signed certificate can therefore satisfy hostname and CertificateVerify checks and enable interception, credential disclosure, traffic modification, and malicious responses. This issue is fixed in version 7.23.

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-2026-73251.json"