UBUNTU-CVE-2026-73256

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Source
https://ubuntu.com/security/CVE-2026-73256
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73256.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-73256
Upstream
Published
2026-08-20T18:16:00Z
Modified
2026-10-17T13:01:01Z
Severity
  • 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 7.22, a remote unauthenticated attacker can exploit an HTTP/1.0 reverse-proxy deployment by sending a request with Transfer-Encoding: chunked and conflicting framing. The http_cb() function in src/http.c tests hm.proto.len with an impossible greater-than-eight condition even though mg_http_parse() requires an eight-byte protocol string, so is_http_1_0 is never set. Mongoose consequently processes chunked encoding that an HTTP/1.0 proxy can ignore, enabling request smuggling and unauthorized access or state changes. 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-2026-73256.json"