Skip to content
Heist/ feed
Back to feed
Medium

cflow — security advisory

Type: advisorySources: OSVAdvisory ID: UBUNTU-CVE-2020-23856

Use-after-Free vulnerability in cflow 1.6 in the void call(char *name, int line) function at src/parser.c, which could cause a denial of service via the pointer variable caller->callee.

Products
cflow
Affected versions
1:1.4+dfsg1-3ubuntu1, 1:1.4+dfsg1-3ubuntu1.16.04.1~esm1, 1:1.4+dfsg1-3ubuntu1.18.04.1~esm1, 1:1.6-4, 1:1.6-6, 1:1.7-2, 1:1.7-4, 1:1.7-5, 1:1.8-1, 1:1.8-1build1
Fixed versions
Not specified
CVEs
CVE-2020-23856
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 00:37 UTC · Revision 1

Source evidence

UBUNTU-CVE-2020-23856

core-osv · Original source

Published 18 May 2021, 15:15 UTC

Use-after-Free vulnerability in cflow 1.6 in the void call(char *name, int line) function at src/parser.c, which could cause a denial of service via the pointer variable caller->callee.

osv:UBUNTU-CVE-2020-23856

cflow

Fixed versions: Not specified

cflow

Fixed versions: Not specified

cflow

Fixed versions: Not specified

cflow

Fixed versions: Not specified

cflow

Fixed versions: Not specified

cflow

Fixed versions: Not specified

cflow

Fixed versions: Not specified

cflow

Fixed versions: Not specified

Complete source record
{
  "id": "a0a884297fe0d777eea09fd5f2c3c268e1c1eda6839ee4b6f8c8df9da1b3987a",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2020-23856",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2020-23856",
    "summary": "Use-after-Free vulnerability in cflow 1.6 in the void call(char *name, int line) function at src/parser.c, which could cause a denial of service via the pointer variable caller->callee.",
    "evidence": "osv:UBUNTU-CVE-2020-23856",
    "products": [
      {
        "name": {
          "value": "cflow",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:1.4+dfsg1-3ubuntu1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "1:1.4+dfsg1-3ubuntu1.16.04.1~esm1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "cflow",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:1.4+dfsg1-3ubuntu1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "1:1.4+dfsg1-3ubuntu1.18.04.1~esm1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "cflow",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:1.6-4",
            "evidence": "/affected/2/versions"
          }
        ]
      },
      {
        "name": {
          "value": "cflow",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:1.6-4",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "1:1.6-6",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "1:1.7-2",
            "evidence": "/affected/3/versions"
          }
        ]
      },
      {
        "name": {
          "value": "cflow",
          "evidence": "/affected/4/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:1.7-4",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "1:1.7-5",
            "evidence": "/affected/4/versions"
          }
        ]
      },
      {
        "name": {
          "value": "cflow",
          "evidence": "/affected/5/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:1.7-5",
            "evidence": "/affected/5/versions"
          },
          {
            "value": "1:1.8-1",
            "evidence": "/affected/5/versions"
          }
        ]
      },
      {
        "name": {
          "value": "cflow",
          "evidence": "/affected/6/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:1.8-1build1",
            "evidence": "/affected/6/versions"
          }
        ]
      },
      {
        "name": {
          "value": "cflow",
          "evidence": "/affected/7/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1:1.8-1",
            "evidence": "/affected/7/versions"
          },
          {
            "value": "1:1.8-1build1",
            "evidence": "/affected/7/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "UBUNTU-CVE-2020-23856",
      "aliases": [
        "UBUNTU-CVE-2020-23856"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "cflow",
            "purl": "pkg:deb/ubuntu/cflow?arch=source&distro=esm-apps%2Fxenial",
            "ecosystem": "Ubuntu:Pro:16.04:LTS"
          },
          "versions": [
            "1:1.4+dfsg1-3ubuntu1",
            "1:1.4+dfsg1-3ubuntu1.16.04.1~esm1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-23856.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "cflow",
                "binary_version": "1:1.4+dfsg1-3ubuntu1.16.04.1~esm1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "cflow",
            "purl": "pkg:deb/ubuntu/cflow?arch=source&distro=esm-apps%2Fbionic",
            "ecosystem": "Ubuntu:Pro:18.04:LTS"
          },
          "versions": [
            "1:1.4+dfsg1-3ubuntu1",
            "1:1.4+dfsg1-3ubuntu1.18.04.1~esm1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-23856.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "cflow",
                "binary_version": "1:1.4+dfsg1-3ubuntu1.18.04.1~esm1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "cflow",
            "purl": "pkg:deb/ubuntu/cflow?arch=source&distro=focal",
            "ecosystem": "Ubuntu:20.04:LTS"
          },
          "versions": [
            "1:1.6-4"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-23856.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "cflow",
                "binary_version": "1:1.6-4"
              },
              {
                "binary_name": "cflow-l10n",
                "binary_version": "1:1.6-4"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "cflow",
            "purl": "pkg:deb/ubuntu/cflow?arch=source&distro=jammy",
            "ecosystem": "Ubuntu:22.04:LTS"
          },
          "versions": [
            "1:1.6-4",
            "1:1.6-6",
            "1:1.7-2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-23856.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "cflow",
                "binary_version": "1:1.7-2"
              },
              {
                "binary_name": "cflow-l10n",
                "binary_version": "1:1.7-2"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "cflow",
            "purl": "pkg:deb/ubuntu/cflow?arch=source&distro=noble",
            "ecosystem": "Ubuntu:24.04:LTS"
          },
          "versions": [
            "1:1.7-4",
            "1:1.7-5"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-23856.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "cflow",
                "binary_version": "1:1.7-5"
              },
              {
                "binary_name": "cflow-l10n",
                "binary_version": "1:1.7-5"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "cflow",
            "purl": "pkg:deb/ubuntu/cflow?arch=source&distro=questing",
            "ecosystem": "Ubuntu:25.10"
          },
          "versions": [
            "1:1.7-5",
            "1:1.8-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-23856.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "cflow",
                "binary_version": "1:1.8-1"
              },
              {
                "binary_name": "cflow-l10n",
                "binary_version": "1:1.8-1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "cflow",
            "purl": "pkg:deb/ubuntu/cflow?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "1:1.8-1build1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-23856.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "cflow",
                "binary_version": "1:1.8-1build1"
              },
              {
                "binary_name": "cflow-l10n",
                "binary_version": "1:1.8-1build1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "cflow",
            "purl": "pkg:deb/ubuntu/cflow?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "1:1.8-1",
            "1:1.8-1build1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2020/UBUNTU-CVE-2020-23856.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "cflow",
                "binary_version": "1:1.8-1build1"
              },
              {
                "binary_name": "cflow-l10n",
                "binary_version": "1:1.8-1build1"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T12:55:52.327729506Z",
      "provider": "osv",
      "upstream": [
        "CVE-2020-23856"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2020-23856",
        "https://lists.gnu.org/archive/html/bug-cflow/2020-07/msg00000.html",
        "https://github.com/yangjiageng/PoC/blob/master/PoC_cflow_uaf_parser_line1284",
        "https://www.cve.org/CVERecord?id=CVE-2020-23856"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2020-23856",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 354194,
  "published_at": "2021-05-18T15:15:00+00:00"
}