CVE-2024-27280 (GCVE-0-2024-27280)

Vulnerability from cvelistv5 – Published: 2024-05-08 20:51 – Updated: 2025-11-04 17:17
VLAI
Summary
A buffer-overread issue was discovered in StringIO 3.0.1, as distributed in Ruby 3.0.x through 3.0.6 and 3.1.x through 3.1.4. The ungetbyte and ungetc methods on a StringIO can read past the end of a string, and a subsequent call to StringIO.gets may return the memory value. 3.0.3 is the main fixed version; however, for Ruby 3.0 users, a fixed version is stringio 3.0.1.1, and for Ruby 3.1 users, a fixed version is stringio 3.0.1.2.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-05-09 18:08 UTC
CWE
  • n/a
  • CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Assigner
mitre CNA under the mitre root
CNA scorecard E 28/100 over 2309 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
ruby-lang ruby Affected: 3.0.3 , ≤ 3.0.6 (custom)
    cpe:2.3:a:ruby-lang:ruby:-:*:*:*:*:*:*:*
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "affected": [
          {
            "cpes": [
              "cpe:2.3:a:ruby-lang:ruby:-:*:*:*:*:*:*:*"
            ],
            "defaultStatus": "unknown",
            "product": "ruby",
            "vendor": "ruby-lang",
            "versions": [
              {
                "lessThanOrEqual": "3.0.6",
                "status": "affected",
                "version": "3.0.3",
                "versionType": "custom"
              }
            ]
          }
        ],
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2024-27280",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-09T18:08:05.682025Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-120",
                "description": "CWE-120 Buffer Copy without Checking Size of Input (\u0027Classic Buffer Overflow\u0027)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-06-04T17:46:36.722Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-04T17:17:47.556Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://hackerone.com/reports/1399856"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://www.ruby-lang.org/en/news/2024/03/21/buffer-overread-cve-2024-27280/"
          },
          {
            "url": "https://security.netapp.com/advisory/ntap-20250502-0003/"
          },
          {
            "url": "http://seclists.org/fulldisclosure/2025/Sep/55"
          },
          {
            "url": "http://seclists.org/fulldisclosure/2025/Sep/54"
          },
          {
            "url": "http://seclists.org/fulldisclosure/2025/Sep/53"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2024/09/msg00000.html"
          },
          {
            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/27LUWREIFTP3MQAW7QE4PJM4DPAQJWXF/"
          },
          {
            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XYDHPHEZI7OQXTQKTDZHGZNPIJH7ZV5N/"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "A buffer-overread issue was discovered in StringIO 3.0.1, as distributed in Ruby 3.0.x through 3.0.6 and 3.1.x through 3.1.4. The ungetbyte and ungetc methods on a StringIO can read past the end of a string, and a subsequent call to StringIO.gets may return the memory value. 3.0.3 is the main fixed version; however, for Ruby 3.0 users, a fixed version is stringio 3.0.1.1, and for Ruby 3.1 users, a fixed version is stringio 3.0.1.2."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2024-05-08T20:51:20.724Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://hackerone.com/reports/1399856"
        },
        {
          "url": "https://www.ruby-lang.org/en/news/2024/03/21/buffer-overread-cve-2024-27280/"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2024-27280",
    "datePublished": "2024-05-08T20:51:20.388Z",
    "dateReserved": "2024-02-22T00:00:00.000Z",
    "dateUpdated": "2025-11-04T17:17:47.556Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2024-27280",
      "date": "2026-10-31",
      "epss": "0.02364",
      "percentile": "0.83798"
    },
    "fkie_nvd": {
      "descriptions": [
        {
          "lang": "en",
          "value": "A buffer-overread issue was discovered in StringIO 3.0.1, as distributed in Ruby 3.0.x through 3.0.6 and 3.1.x through 3.1.4. The ungetbyte and ungetc methods on a StringIO can read past the end of a string, and a subsequent call to StringIO.gets may return the memory value. 3.0.3 is the main fixed version; however, for Ruby 3.0 users, a fixed version is stringio 3.0.1.1, and for Ruby 3.1 users, a fixed version is stringio 3.0.1.2."
        },
        {
          "lang": "es",
          "value": "Se descubri\u00f3 un problema de sobrelectura del b\u00fafer en StringIO 3.0.1, distribuido en Ruby 3.0.x hasta 3.0.6 y 3.1.x hasta 3.1.4. Los m\u00e9todos ungetbyte y ungetc en StringIO pueden leer m\u00e1s all\u00e1 del final de una cadena, y una llamada posterior a StringIO.gets puede devolver el valor de la memoria. 3.0.3 es la versi\u00f3n fija principal; sin embargo, para los usuarios de Ruby 3.0, una versi\u00f3n fija es stringio 3.0.1.1, y para los usuarios de Ruby 3.1, una versi\u00f3n fija es stringio 3.0.1.2."
        }
      ],
      "id": "CVE-2024-27280",
      "lastModified": "2024-11-21T09:04:13.950",
      "metrics": {
        "cvssMetricV31": [
          {
            "cvssData": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            },
            "exploitabilityScore": 3.9,
            "impactScore": 5.9,
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "type": "Secondary"
          }
        ]
      },
      "published": "2024-05-14T15:11:56.940",
      "references": [
        {
          "source": "cve@mitre.org",
          "url": "https://hackerone.com/reports/1399856"
        },
        {
          "source": "cve@mitre.org",
          "url": "https://www.ruby-lang.org/en/news/2024/03/21/buffer-overread-cve-2024-27280/"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "url": "https://hackerone.com/reports/1399856"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "url": "https://www.ruby-lang.org/en/news/2024/03/21/buffer-overread-cve-2024-27280/"
        }
      ],
      "sourceIdentifier": "cve@mitre.org",
      "vulnStatus": "Awaiting Analysis",
      "weaknesses": [
        {
          "description": [
            {
              "lang": "en",
              "value": "CWE-120"
            }
          ],
          "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "type": "Secondary"
        }
      ]
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "n/a",
                "vendor": "n/a",
                "versions": [
                  {
                    "status": "affected",
                    "version": "n/a"
                  }
                ]
              }
            ],
            "source": "cve@mitre.org"
          },
          {
            "affectedData": [
              {
                "cpes": [
                  "cpe:2.3:a:ruby-lang:ruby:-:*:*:*:*:*:*:*"
                ],
                "defaultStatus": "unknown",
                "product": "ruby",
                "vendor": "ruby-lang",
                "versions": [
                  {
                    "lessThanOrEqual": "3.0.6",
                    "status": "affected",
                    "version": "3.0.3",
                    "versionType": "custom"
                  }
                ]
              }
            ],
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "A buffer-overread issue was discovered in StringIO 3.0.1, as distributed in Ruby 3.0.x through 3.0.6 and 3.1.x through 3.1.4. The ungetbyte and ungetc methods on a StringIO can read past the end of a string, and a subsequent call to StringIO.gets may return the memory value. 3.0.3 is the main fixed version; however, for Ruby 3.0 users, a fixed version is stringio 3.0.1.1, and for Ruby 3.1 users, a fixed version is stringio 3.0.1.2."
          },
          {
            "lang": "es",
            "value": "Se descubri\u00f3 un problema de sobrelectura del b\u00fafer en StringIO 3.0.1, distribuido en Ruby 3.0.x hasta 3.0.6 y 3.1.x hasta 3.1.4. Los m\u00e9todos ungetbyte y ungetc en StringIO pueden leer m\u00e1s all\u00e1 del final de una cadena, y una llamada posterior a StringIO.gets puede devolver el valor de la memoria. 3.0.3 es la versi\u00f3n fija principal; sin embargo, para los usuarios de Ruby 3.0, una versi\u00f3n fija es stringio 3.0.1.1, y para los usuarios de Ruby 3.1, una versi\u00f3n fija es stringio 3.0.1.2."
          }
        ],
        "id": "CVE-2024-27280",
        "lastModified": "2026-06-17T07:19:33.770",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2024-27280",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-09T18:08:05.682025Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2024-05-14T15:11:56.940",
        "references": [
          {
            "source": "cve@mitre.org",
            "url": "https://hackerone.com/reports/1399856"
          },
          {
            "source": "cve@mitre.org",
            "url": "https://www.ruby-lang.org/en/news/2024/03/21/buffer-overread-cve-2024-27280/"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "http://seclists.org/fulldisclosure/2025/Sep/53"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "http://seclists.org/fulldisclosure/2025/Sep/54"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "http://seclists.org/fulldisclosure/2025/Sep/55"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://hackerone.com/reports/1399856"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.debian.org/debian-lts-announce/2024/09/msg00000.html"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/27LUWREIFTP3MQAW7QE4PJM4DPAQJWXF/"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XYDHPHEZI7OQXTQKTDZHGZNPIJH7ZV5N/"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://security.netapp.com/advisory/ntap-20250502-0003/"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://www.ruby-lang.org/en/news/2024/03/21/buffer-overread-cve-2024-27280/"
          }
        ],
        "sourceIdentifier": "cve@mitre.org",
        "vulnStatus": "Deferred",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-120"
              }
            ],
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-01-27T11:11:59+00:00",
      "cve": "CVE-2024-27280",
      "id": "CVE-2024-27280",
      "initial_release_date": "2024-03-21T00:00:00+00:00",
      "product_status:fixed": "983",
      "product_status:known_affected": "47",
      "product_status:known_not_affected": "29",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "ruby: Buffer overread vulnerability in StringIO",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-27280.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "low",
      "current_release_date": "2026-10-09T01:16:55Z",
      "cve": "CVE-2024-27280",
      "id": "CVE-2024-27280",
      "initial_release_date": "2024-03-23T03:34:39Z",
      "product_status:known_not_affected": "298",
      "product_status:recommended": "96",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2024-27280",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2024-27280.json",
      "version": "21"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2025-11-03T18:08:20.761Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://hackerone.com/reports/1399856"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://www.ruby-lang.org/en/news/2024/03/21/buffer-overread-cve-2024-27280/"
              },
              {
                "url": "https://security.netapp.com/advisory/ntap-20250502-0003/"
              },
              {
                "url": "http://seclists.org/fulldisclosure/2025/Sep/55"
              },
              {
                "url": "http://seclists.org/fulldisclosure/2025/Sep/54"
              },
              {
                "url": "http://seclists.org/fulldisclosure/2025/Sep/53"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "affected": [
              {
                "cpes": [
                  "cpe:2.3:a:ruby-lang:ruby:-:*:*:*:*:*:*:*"
                ],
                "defaultStatus": "unknown",
                "product": "ruby",
                "vendor": "ruby-lang",
                "versions": [
                  {
                    "lessThanOrEqual": "3.0.6",
                    "status": "affected",
                    "version": "3.0.3",
                    "versionType": "custom"
                  }
                ]
              }
            ],
            "metrics": [
              {
                "cvssV3_1": {
                  "attackComplexity": "LOW",
                  "attackVector": "NETWORK",
                  "availabilityImpact": "HIGH",
                  "baseScore": 9.8,
                  "baseSeverity": "CRITICAL",
                  "confidentialityImpact": "HIGH",
                  "integrityImpact": "HIGH",
                  "privilegesRequired": "NONE",
                  "scope": "UNCHANGED",
                  "userInteraction": "NONE",
                  "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                  "version": "3.1"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2024-27280",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2024-05-09T18:08:05.682025Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-120",
                    "description": "CWE-120 Buffer Copy without Checking Size of Input (\u0027Classic Buffer Overflow\u0027)",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2024-05-09T18:04:48.719Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "n/a",
              "vendor": "n/a",
              "versions": [
                {
                  "status": "affected",
                  "version": "n/a"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "A buffer-overread issue was discovered in StringIO 3.0.1, as distributed in Ruby 3.0.x through 3.0.6 and 3.1.x through 3.1.4. The ungetbyte and ungetc methods on a StringIO can read past the end of a string, and a subsequent call to StringIO.gets may return the memory value. 3.0.3 is the main fixed version; however, for Ruby 3.0 users, a fixed version is stringio 3.0.1.1, and for Ruby 3.1 users, a fixed version is stringio 3.0.1.2."
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "description": "n/a",
                  "lang": "en",
                  "type": "text"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2024-05-08T20:51:20.724Z",
            "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
            "shortName": "mitre"
          },
          "references": [
            {
              "url": "https://hackerone.com/reports/1399856"
            },
            {
              "url": "https://www.ruby-lang.org/en/news/2024/03/21/buffer-overread-cve-2024-27280/"
            }
          ]
        }
      },
      "cveMetadata": {
        "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "assignerShortName": "mitre",
        "cveId": "CVE-2024-27280",
        "datePublished": "2024-05-08T20:51:20.388Z",
        "dateReserved": "2024-02-22T00:00:00.000Z",
        "dateUpdated": "2025-11-03T18:08:20.761Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    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.