GHSA-CPWX-VRP4-4PQ7

Vulnerability from github – Published: 2025-03-05 20:40 – Updated: 2025-11-03 22:54
VLAI?
Summary
Jinja2 vulnerable to sandbox breakout through attr filter selecting format method
Details

An oversight in how the Jinja sandboxed environment interacts with the |attr filter allows an attacker that controls the content of a template to execute arbitrary Python code.

To exploit the vulnerability, an attacker needs to control the content of a template. Whether that is the case depends on the type of application using Jinja. This vulnerability impacts users of applications which execute untrusted templates.

Jinja's sandbox does catch calls to str.format and ensures they don't escape the sandbox. However, it's possible to use the |attr filter to get a reference to a string's plain format method, bypassing the sandbox. After the fix, the |attr filter no longer bypasses the environment's attribute lookup.

Severity ?
5.4 (Medium)
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.5"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "Jinja2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-27516"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1336"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-03-05T20:40:14Z",
    "nvd_published_at": "2025-03-05T21:15:20Z",
    "severity": "MODERATE"
  },
  "details": "An oversight in how the Jinja sandboxed environment interacts with the `|attr` filter allows an attacker that controls the content of a template to execute arbitrary Python code.\n\nTo exploit the vulnerability, an attacker needs to control the content of a template. Whether that is the case depends on the type of application using Jinja. This vulnerability impacts users of applications which execute untrusted templates.\n\nJinja\u0027s sandbox does catch calls to `str.format` and ensures they don\u0027t escape the sandbox. However, it\u0027s possible to use the `|attr` filter to get a reference to a string\u0027s plain format method, bypassing the sandbox. After the fix, the `|attr` filter no longer bypasses the environment\u0027s attribute lookup.",
  "id": "GHSA-cpwx-vrp4-4pq7",
  "modified": "2025-11-03T22:54:41Z",
  "published": "2025-03-05T20:40:14Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pallets/jinja/security/advisories/GHSA-cpwx-vrp4-4pq7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-27516"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pallets/jinja/commit/90457bbf33b8662926ae65cdde4c4c32e756e403"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pallets/jinja"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/04/msg00022.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/04/msg00045.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Jinja2 vulnerable to sandbox breakout through attr filter selecting format method"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

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.



Detection rules are retrieved from Rulezet.