Vulnerability-Lookup

RHSA-2026:43940

Vulnerability from csaf_redhat - Published: 2026-07-22 21:23 - Updated: 2026-08-24 13:27

Summary

Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

Severity

Important

Notes

Topic: An update for Red Hat Hardened Images RPMs is now available.

Details: This update includes the following RPMs: python-jinja2: * python3-jinja2+i18n-3.1.6-10.1.hum1 (noarch) * python3-jinja2-3.1.6-10.1.hum1 (noarch) * python-jinja2-3.1.6-10.1.hum1.src (src)

Terms of Use: This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.

CVE-2025-27516

A flaw was found in Jinja. In affected versions, an oversight in how the Jinja sandboxed environment interacts with the `|attr` filter allows an attacker who 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 that 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.

7.3 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

CWE-1336 - Improper Neutralization of Special Elements Used in a Template Engine

Affected products

Fixed 2 products

Product	Identifier	Version	Remediation
Unresolved product id: Red Hat Hardened Images:python-jinja2-main@noarch		—	Vendor Fix fix
Unresolved product id: Red Hat Hardened Images:python-jinja2-main@src		—	Vendor Fix fix

Threats

Impact Important

References

11 references

URL	Category
https://access.redhat.com/errata/RHSA-2026:43940	self
https://images.redhat.com/	external
https://access.redhat.com/security/cve/CVE-2025-27516	external
https://access.redhat.com/security/updates/classi…	external
https://security.access.redhat.com/data/csaf/v2/a…	self
https://access.redhat.com/security/cve/CVE-2025-27516	self
https://bugzilla.redhat.com/show_bug.cgi?id=2350190	external
https://www.cve.org/CVERecord?id=CVE-2025-27516	external
https://nvd.nist.gov/vuln/detail/CVE-2025-27516	external
https://github.com/pallets/jinja/commit/90457bbf3…	external
https://github.com/pallets/jinja/security/advisor…	external

JSON

To clipboard

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        "text": "This update includes the following RPMs:\n\npython-jinja2:\n  * python3-jinja2+i18n-3.1.6-10.1.hum1 (noarch)\n  * python3-jinja2-3.1.6-10.1.hum1 (noarch)\n  * python-jinja2-3.1.6-10.1.hum1.src (src)",
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      "cve": "CVE-2025-27516",
      "cwe": {
        "id": "CWE-1336",
        "name": "Improper Neutralization of Special Elements Used in a Template Engine"
      },
      "discovery_date": "2025-03-05T21:01:07.674606+00:00",
      "ids": [
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          "text": "2350190"
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      "notes": [
        {
          "category": "description",
          "text": "A flaw was found in Jinja. In affected versions, an oversight in how the Jinja sandboxed environment interacts with the `|attr` filter allows an attacker who 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 that execute untrusted templates. Jinja\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.",
          "title": "Vulnerability description"
        },
        {
          "category": "summary",
          "text": "jinja2: Jinja sandbox breakout through attr filter selecting format method",
          "title": "Vulnerability summary"
        },
        {
          "category": "other",
          "text": "This vulnerability is rated as important severity due to the potential for an attacker to bypass Jinja\u0027s sandbox by exploiting the |attr filter, by controlling template content, an attacker can execute arbitrary Python code, impacting the integrity, confidentiality, and availability of the system. While the attack requires user interaction to trigger untrusted templates, the risk is significant in applications that allow such templates to be executed.",
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        {
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        {
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        }
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      "remediations": [
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          "category": "vendor_fix",
          "date": "2026-07-22T21:23:57+00:00",
          "details": "For details on how to apply this update, which includes the changes described in this advisory, refer to:\nhttps://images.redhat.com/",
          "product_ids": [
            "Red Hat Hardened Images:python-jinja2-main@noarch",
            "Red Hat Hardened Images:python-jinja2-main@src"
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            "category": "none"
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        }
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      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
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          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Important"
        }
      ],
      "title": "jinja2: Jinja sandbox breakout through attr filter selecting format method"
    }
  ]
}

CVE-2025-27516 (GCVE-0-2025-27516)

Vulnerability from cvelistv5 – Published: 2025-03-05 20:40 – Updated: 2026-02-26 19:09

Title

Jinja sandbox breakout through attr filter selecting format method

Summary

Jinja is an extensible templating engine. Prior to 3.1.6, 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. This vulnerability is fixed in 3.1.6.

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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-07-31 03:56 UTC

CWE

CWE-1336 - Improper Neutralization of Special Elements Used in a Template Engine

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/pallets/jinja/security/advisor…	x_refsource_CONFIRM
https://github.com/pallets/jinja/commit/90457bbf3…	x_refsource_MISC
https://lists.debian.org/debian-lts-announce/2025…
https://lists.debian.org/debian-lts-announce/2025…

Impacted products

1 product

Vendor	Product	Version
pallets	jinja	Affected: < 3.1.6

Show details on NVD website

JSON

To clipboard

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            "other": {
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                "id": "CVE-2025-27516",
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                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-07-31T03:56:03.356670Z",
                "version": "2.0.3"
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        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/04/msg00045.html"
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            "url": "https://lists.debian.org/debian-lts-announce/2025/04/msg00022.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "jinja",
          "vendor": "pallets",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.1.6"
            }
          ]
        }
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      "descriptions": [
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          "lang": "en",
          "value": "Jinja is an extensible templating engine. Prior to 3.1.6, 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\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. This vulnerability is fixed in 3.1.6."
        }
      ],
      "metrics": [
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          "cvssV4_0": {
            "attackComplexity": "LOW",
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            "baseSeverity": "MEDIUM",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
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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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

RHSA-2026:43940

CVE-2025-27516 (GCVE-0-2025-27516)

Tags

Sightings

Nomenclature