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mongoose — security advisory

Type: advisorySources: OSVAdvisory ID: UBUNTU-CVE-2026-73254

Mongoose is an embedded web server and network library. Prior to 7.22, an attacker who can create a file with an HTML payload in its name can trigger stored cross-site scripting when a user browses a directory served with MG_ENABLE_DIRLIST. The printdirentry() path called by listdir() in src/http.c URL-encodes the href but inserts the raw filesystem filename into the HTML link text. The browser executes the injected markup in the Mongoose origin, which can expose session data or permit actions as the victim. This issue is fixed in version 7.22.

Products
mongoose
Affected versions
7.21+ds-1, 7.21+ds-2, 7.22+ds-1, 7.23+ds-1
Fixed versions
Not specified
CVEs
CVE-2026-73254
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 03:15 UTC · Revision 1

Source evidence

UBUNTU-CVE-2026-73254

core-osv · Original source

Published 20 Aug 2026, 18:16 UTC

Mongoose is an embedded web server and network library. Prior to 7.22, an attacker who can create a file with an HTML payload in its name can trigger stored cross-site scripting when a user browses a directory served with MG_ENABLE_DIRLIST. The printdirentry() path called by listdir() in src/http.c URL-encodes the href but inserts the raw filesystem filename into the HTML link text. The browser executes the injected markup in the Mongoose origin, which can expose session data or permit actions as the victim. This issue is fixed in version 7.22.

osv:UBUNTU-CVE-2026-73254

mongoose

Fixed versions: Not specified

Complete source record
{
  "id": "8b028acf60a4fb7cf07365b5219fff42f620a9cbe9a7e5b76a1ab347d2baf1eb",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-73254",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-73254",
    "summary": "Mongoose is an embedded web server and network library. Prior to 7.22, an attacker who can create a file with an HTML payload in its name can trigger stored cross-site scripting when a user browses a directory served with MG_ENABLE_DIRLIST. The printdirentry() path called by listdir() in src/http.c URL-encodes the href but inserts the raw filesystem filename into the HTML link text. The browser executes the injected markup in the Mongoose origin, which can expose session data or permit actions as the victim. This issue is fixed in version 7.22.",
    "evidence": "osv:UBUNTU-CVE-2026-73254",
    "products": [
      {
        "name": {
          "value": "mongoose",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "7.21+ds-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "7.21+ds-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "7.22+ds-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "7.23+ds-1",
            "evidence": "/affected/0/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "UBUNTU-CVE-2026-73254",
      "aliases": [
        "UBUNTU-CVE-2026-73254"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "mongoose",
            "purl": "pkg:deb/ubuntu/mongoose?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "7.21+ds-1",
            "7.21+ds-2",
            "7.22+ds-1",
            "7.23+ds-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73254.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "mongoose-webserver-source",
                "binary_version": "7.23+ds-1"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T13:01:02.774318983Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-73254"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-73254",
        "https://www.cve.org/CVERecord?id=CVE-2026-73254"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-73254",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 360898,
  "published_at": "2026-08-20T18:16:00+00:00"
}