UBUNTU-CVE-2026-73261

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/CVE-2026-73261
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73261.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-73261
Upstream
Published
2026-10-14T19:17:00Z
Modified
2026-10-28T20:17:48Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TCP/IP stack enabled by MG_ENABLE_TCPIP in src/net_builtin.c does not reject a TCP option whose declared opts[1] length exceeds the remaining option bytes. In handle_opt(), a NOP followed by a truncated MSS option causes opts[3] to be read outside the declared options area and used as the low byte of dmss. An unauthenticated remote peer can corrupt the per-connection MSS value so later mg_send() calls transmit truncated or zero-length application payloads while the TCP connection otherwise appears healthy. 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-2026-73261.json"