Vulnerability-Lookup

FKIE_CVE-2021-33624

Vulnerability from fkie_nvd - Published: 2021-06-23 16:15 - Updated: 2026-06-17 03:54

Severity

4.7 (Medium) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Summary

In kernel/bpf/verifier.c in the Linux kernel before 5.12.13, a branch can be mispredicted (e.g., because of type confusion) and consequently an unprivileged BPF program can read arbitrary memory locations via a side-channel attack, aka CID-9183671af6db.

References

URL	Tags
cve@mitre.org	http://www.openwall.com/lists/oss-security/2021/06/21/1	Exploit, Mailing List, Third Party Advisory
cve@mitre.org	https://github.com/benschlueter/CVE-2021-33624
cve@mitre.org	https://github.com/torvalds/linux/commit/9183671af6dbf60a1219371d4ed73e23f43b49db	Patch, Third Party Advisory
cve@mitre.org	https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html	Issue Tracking, Third Party Advisory
cve@mitre.org	https://www.usenix.org/conference/usenixsecurity21/presentation/kirzner	Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	http://www.openwall.com/lists/oss-security/2021/06/21/1	Exploit, Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://github.com/torvalds/linux/commit/9183671af6dbf60a1219371d4ed73e23f43b49db	Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html	Issue Tracking, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://www.usenix.org/conference/usenixsecurity21/presentation/kirzner	Third Party Advisory

Impacted products

	Vendor	Product	Version
	linux	linux_kernel	*
	debian	debian_linux	9.0

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "4C096241-6457-4DB4-80C3-DD650F628184",
              "versionEndExcluding": "5.12.13",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*",
              "matchCriteriaId": "DEECE5FC-CACF-4496-A3E7-164736409252",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In kernel/bpf/verifier.c in the Linux kernel before 5.12.13, a branch can be mispredicted (e.g., because of type confusion) and consequently an unprivileged BPF program can read arbitrary memory locations via a side-channel attack, aka CID-9183671af6db."
    },
    {
      "lang": "es",
      "value": "En el archivo kernel/bpf/verifier.c en el kernel de Linux versiones anteriores a 5.12.13, una rama puede ser mal predicha (por ejemplo, debido a la confusi\u00f3n de tipos) y, en consecuencia, un programa BPF no privilegiado puede leer ubicaciones de memoria arbitrarias por medio de un ataque de canal lateral, tambi\u00e9n conocido como CID-9183671af6db"
    }
  ],
  "id": "CVE-2021-33624",
  "lastModified": "2026-06-17T03:54:53.270",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "LOCAL",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 4.7,
          "confidentialityImpact": "COMPLETE",
          "integrityImpact": "NONE",
          "vectorString": "AV:L/AC:M/Au:N/C:C/I:N/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 3.4,
        "impactScore": 6.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
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        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 4.7,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
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  },
  "published": "2021-06-23T16:15:07.957",
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      "url": "http://www.openwall.com/lists/oss-security/2021/06/21/1"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://github.com/benschlueter/CVE-2021-33624"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://github.com/torvalds/linux/commit/9183671af6dbf60a1219371d4ed73e23f43b49db"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "url": "https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://www.usenix.org/conference/usenixsecurity21/presentation/kirzner"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Exploit",
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "http://www.openwall.com/lists/oss-security/2021/06/21/1"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "url": "https://github.com/torvalds/linux/commit/9183671af6dbf60a1219371d4ed73e23f43b49db"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "url": "https://lists.debian.org/debian-lts-announce/2021/10/msg00010.html"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://www.usenix.org/conference/usenixsecurity21/presentation/kirzner"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-843"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2021-33624 (GCVE-0-2021-33624)

Vulnerability from cvelistv5 – Published: 2021-06-23 15:37 – Updated: 2025-11-11 15:19

Summary

Severity

No CVSS data available.

CWE

Assigner

mitre mitre root

References

5 references

URL	Tags
https://www.usenix.org/conference/usenixsecurity2…
http://www.openwall.com/lists/oss-security/2021/06/21/1
https://github.com/torvalds/linux/commit/9183671a…
https://lists.debian.org/debian-lts-announce/2021…	mailing-list
https://github.com/benschlueter/CVE-2021-33624

Show details on NVD website

JSON

To clipboard

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          },
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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.

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.

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FKIE_CVE-2021-33624

CVE-2021-33624 (GCVE-0-2021-33624)

Tags

Sightings

Nomenclature

Related by attack behaviour