Vulnerability-Lookup

CVE-2020-21686 (GCVE-0-2020-21686)

Vulnerability from cvelistv5 – Published: 2023-08-22 00:00 – Updated: 2024-10-07 15:09

Summary

A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.

Severity

No CVSS data available.

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-10-07 15:08 UTC

CWE

n/a
CWE-562 - Return of Stack Variable Address

Assigner

mitre mitre root

References

1 reference

URL	Tags
https://bugzilla.nasm.us/show_bug.cgi?id=3392643

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2020-21686

Vulnerability from fkie_nvd - Published: 2023-08-22 19:16 - Updated: 2026-06-17 03:03

Severity

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

Summary

A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.

References

	URL	Tags
	cve@mitre.org	https://bugzilla.nasm.us/show_bug.cgi?id=3392643	Exploit, Issue Tracking, Vendor Advisory
	af854a3a-2127-422b-91ae-364da2661108	https://bugzilla.nasm.us/show_bug.cgi?id=3392643	Exploit, Issue Tracking, Vendor Advisory

Impacted products

	Vendor	Product	Version
	nasm	netwide_assembler	*

JSON

To clipboard

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GHSA-F5W2-2H32-HMG6

Vulnerability from github – Published: 2023-08-22 21:30 – Updated: 2024-04-04 07:05

Details

A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.

Severity

5.5 (Medium)


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

Show details on source website

JSON

To clipboard

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  "id": "GHSA-f5w2-2h32-hmg6",
  "modified": "2024-04-04T07:05:56Z",
  "published": "2023-08-22T21:30:25Z",
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}

GSD-2020-21686

Vulnerability from gsd - Updated: 2023-12-13 01:21

Details

A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.

Aliases

CVE-2020-21686

Aliases

CVE-2020-21686

JSON

To clipboard

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OESA-2024-1814 (CVE-2020-21685)

Vulnerability from osv_openeuler – Published: 2024-07-05 11:07 – Updated: 2026-08-06 11:07 – Source website

Summary

nasm security update

Details

NASM is the Netwide Assembler, a free portable assembler for the Intel 80x86 microprocessor series, using primarily the traditional Intel instruction mnemonics and syntax. It also provides tools in RDOFF binary format, includes linker, library manager, loader, and information dump.

Security Fix(es):

Buffer Overflow vulnerability in hash_findi function in hashtbl.c in nasm 2.15rc0 allows remote attackers to cause a denial of service via crafted asm file.(CVE-2020-21685)

A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.(CVE-2020-21686)

Buffer Overflow vulnerability in scan function in stdscan.c in nasm 2.15rc0 allows remote attackers to cause a denial of service via crafted asm file.(CVE-2020-21687)

Severity

5.5 (Medium)


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

References

URL

Type

	https://www.openeuler.org/zh/security/security-bu…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2020-21685	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2020-21686	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2020-21687	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "nasm-2.15.05-1.oe2003sp4.aarch64.rpm",
          "nasm-debuginfo-2.15.05-1.oe2003sp4.aarch64.rpm",
          "nasm-debugsource-2.15.05-1.oe2003sp4.aarch64.rpm"
        ],
        "noarch": [
          "nasm-help-2.15.05-1.oe2003sp4.noarch.rpm"
        ],
        "src": [
          "nasm-2.15.05-1.oe2003sp4.src.rpm"
        ],
        "x86_64": [
          "nasm-2.15.05-1.oe2003sp4.x86_64.rpm",
          "nasm-debuginfo-2.15.05-1.oe2003sp4.x86_64.rpm",
          "nasm-debugsource-2.15.05-1.oe2003sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:20.03-LTS-SP4",
        "name": "nasm",
        "purl": "pkg:rpm/openEuler/nasm\u0026distro=openEuler-20.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.15.05-1.oe2003sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "Medium"
  },
  "details": "NASM is the Netwide Assembler, a free portable assembler for the Intel 80x86 microprocessor series, using primarily the traditional Intel instruction mnemonics and syntax. It also provides tools in RDOFF binary format, includes linker, library manager, loader, and information dump.\r\n\r\nSecurity Fix(es):\r\n\r\nBuffer Overflow vulnerability in hash_findi function in hashtbl.c in nasm 2.15rc0 allows remote attackers to cause a denial of service via crafted asm file.(CVE-2020-21685)\r\n\r\nA stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.(CVE-2020-21686)\r\n\r\nBuffer Overflow vulnerability in scan function in stdscan.c in nasm 2.15rc0 allows remote attackers to cause a denial of service via crafted asm file.(CVE-2020-21687)",
  "id": "OESA-2024-1814",
  "modified": "2026-08-06T11:07:16Z",
  "published": "2024-07-05T11:07:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2024-1814"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-21685"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-21686"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-21687"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "nasm security update",
  "upstream": [
    "CVE-2020-21685",
    "CVE-2020-21686",
    "CVE-2020-21687"
  ]
}

UBUNTU-CVE-2020-21686 (CVE-2020-21686)

Vulnerability from osv_ubuntu – Published: 2023-08-22 19:16 – Updated: 2025-10-24 04:48 – Source website

Details

A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.

Severity

5.5 (Medium)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2020-21686	REPORT
	https://bugzilla.nasm.us/show_bug.cgi?id=3392643	REPORT
	https://www.cve.org/CVERecord?id=CVE-2020-21686	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nasm",
            "binary_version": "2.11.08-1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "nasm",
        "purl": "pkg:deb/ubuntu/nasm@2.11.08-1ubuntu0.1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.11.06-1really2.11.05-1",
        "2.11.08-1",
        "2.11.08-1ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nasm",
            "binary_version": "2.13.02-0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "nasm",
        "purl": "pkg:deb/ubuntu/nasm@2.13.02-0.1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.13.01-2",
        "2.13.02-0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "nasm",
            "binary_version": "2.14.02-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "nasm",
        "purl": "pkg:deb/ubuntu/nasm@2.14.02-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.14.02-1"
      ]
    }
  ],
  "aliases": [],
  "details": "A stack-use-after-scope issue discovered in expand_mmac_params function in preproc.c in nasm before 2.15.04 allows remote attackers to cause a denial of service via crafted asm file.",
  "id": "UBUNTU-CVE-2020-21686",
  "modified": "2025-10-24T04:48:39Z",
  "published": "2023-08-22T19:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2020-21686"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.nasm.us/show_bug.cgi?id=3392643"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2020-21686"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2020-21686"
  ]
}

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.

Action not permitted

CVE-2020-21686 (GCVE-0-2020-21686)

FKIE_CVE-2020-21686

GHSA-F5W2-2H32-HMG6

GSD-2020-21686

OESA-2024-1814 (CVE-2020-21685)

UBUNTU-CVE-2020-21686 (CVE-2020-21686)

Tags

Sightings

Nomenclature

Related by attack behaviour