Vulnerability-Lookup

OESA-2021-1159 (CVE-2021-28834)

Vulnerability from osv_openeuler – Published: 2021-05-06 11:04 – Updated: 2026-08-06 11:04 – Source website

Summary

rubygem-kramdown security update

Details

The package is fast yet-another-markdown-parser, pure Ruby, using a strict syntax definition and supporting several common extensions.

Security Fix(es):

Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.(CVE-2021-28834)

Severity

9.8 (Critical)


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

References

URL

Type

	https://openeuler.org/en/security/safety-bulletin…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2021-28834	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "noarch": [
          "rubygem-kramdown-2.1.0-2.oe1.noarch.rpm",
          "rubygem-kramdown-help-2.1.0-2.oe1.noarch.rpm"
        ],
        "src": [
          "rubygem-kramdown-2.1.0-2.oe1.src.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:20.03-LTS-SP1",
        "name": "rubygem-kramdown",
        "purl": "pkg:rpm/openEuler/rubygem-kramdown\u0026distro=openEuler-20.03-LTS-SP1"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.0-2.oe1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "Critical"
  },
  "details": "The package is fast yet-another-markdown-parser, pure Ruby, using a strict syntax definition and supporting several common extensions.\r\n\r\nSecurity Fix(es):\r\n\r\nKramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.(CVE-2021-28834)",
  "id": "OESA-2021-1159",
  "modified": "2026-08-06T11:04:23Z",
  "published": "2021-05-06T11:04:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2021-1159"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28834"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "rubygem-kramdown security update",
  "upstream": [
    "CVE-2021-28834"
  ]
}

CVE-2021-28834 (GCVE-0-2021-28834)

Vulnerability from cvelistv5 – Published: 2021-03-19 06:51 – Updated: 2024-08-03 21:55

Summary

Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.

Severity

No CVSS data available.

CWE

Assigner

mitre mitre root

References

7 references

URL	Tags
https://github.com/gettalong/kramdown/pull/708	x_refsource_MISC
https://gitlab.com/gitlab-org/gitlab/-/commit/179…	x_refsource_MISC
https://github.com/gettalong/kramdown/compare/REL…	x_refsource_MISC
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisoryx_refsource_FEDORA
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisoryx_refsource_FEDORA
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisoryx_refsource_FEDORA
https://www.debian.org/security/2021/dsa-4890	vendor-advisoryx_refsource_DEBIAN

Show details on NVD website

JSON

To clipboard

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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.