CVE-2026-73257

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Source
https://cve.org/CVERecord?id=CVE-2026-73257
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73257.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-73257
Aliases
  • GHSA-5wfq-r6mr-wqp6
Downstream
Published
2026-08-20T17:30:58Z
Modified
2026-10-01T03:47:33Z
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
Summary
Mongoose: Content-Length + Transfer-Encoding coexistence enables request smuggling
Details

Mongoose is an embedded web server and network library. Priro to version 7.22, a remote unauthenticated attacker can send an HTTP request containing both Content-Length and Transfer-Encoding: chunked. The cl_count and te_count checks in the mg_http_parse() and http_cb() paths in src/http.c accept both headers and prioritize chunked encoding, while a Content-Length-preferring reverse proxy can use a different request boundary. This CL.TE desynchronization can inject requests that access or modify resources in another user context. This issue is fixed in version 7.22.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-444"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73257.json"
}
References

Affected packages

Git / github.com/cesanta/mongoose

Affected ranges

Type
GIT
Repo
https://github.com/cesanta/mongoose
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
beb73a65a99619ff349c59037ea5197f27c7e533
Fixed
a9df523f76f43a38bd53b4232b9cfd4c16869e71
Database specific
Show details 
{
    "cpe":  "cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:*",
    "extracted_events":  [
        {
            "introduced":  "0"
        },
        {
            "fixed":  "7.22"
        }
    ],
    "source":  [
        "CPE_RANGE",
        "REFERENCES"
    ]
}

Affected versions

3.*
3.2
3.3
3.4
3.5
3.6
3.7
3.8
4.*
4.0
4.1
5.*
5.0
5.1
5.2
5.3
5.4
5.5
5.5_20140120
5.6
6.*
6.0
6.1
6.10
6.11
6.12
6.13
6.14
6.15
6.16
6.17
6.18
6.2
6.3
6.4
6.5
6.6
6.7
6.9
7.*
7.0
7.1
7.11
7.12
7.13
7.14
7.15
7.16
7.17
7.18
7.19
7.2
7.20
7.21
7.3
7.4
7.5
7.6
7.7
7.8

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73257.json"