CVE-2026-18663 (GCVE-0-2026-18663)

Vulnerability from cvelistv5 – Published: 2026-08-12 09:35 – Updated: 2026-08-13 15:41
VLAI
Title
389-ds-base: 389-ds-base: pre-authentication double-free in get_ldapmessage_controls_ext() via critical session tracking control
Summary
A flaw was found in 389-ds-base. The get_ldapmessage_controls_ext() function frees the parsed controls array on the Session Tracking critical-control rejection path without clearing the SLAPI_REQCONTROLS pblock slot. Operation teardown then frees the same pointer again, causing a double-free. An unauthenticated remote attacker can trigger this with a single BIND request carrying a critical Session Tracking control, resulting in heap corruption and potential denial of service.
Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-13 15:40 UTC
CWE
Assigner
References
URL Tags
https://access.redhat.com/security/cve/CVE-2026-18663 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2510631 issue-trackingx_refsource_REDHAT
Impacted products
Date Public
2026-08-12 07:21
Credits
Red Hat would like to thank Adam Korczynski (Ada Logics), Arthur Chan (Ada Logics), David Korczynski (Ada Logics), and Team (Anthropic) for reporting this issue.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-18663",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-13T15:40:56.481579Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-13T15:41:09.335Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:directory_server:11"
          ],
          "defaultStatus": "unaffected",
          "packageName": "redhat-ds:11/389-ds-base",
          "product": "Red Hat Directory Server 11",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:directory_server:12"
          ],
          "defaultStatus": "unaffected",
          "packageName": "redhat-ds:12/389-ds-base",
          "product": "Red Hat Directory Server 12",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:directory_server:13"
          ],
          "defaultStatus": "affected",
          "packageName": "389-ds-base",
          "product": "Red Hat Directory Server 13",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:10"
          ],
          "defaultStatus": "affected",
          "packageName": "389-ds-base",
          "product": "Red Hat Enterprise Linux 10",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:6"
          ],
          "defaultStatus": "unaffected",
          "packageName": "389-ds-base",
          "product": "Red Hat Enterprise Linux 6",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:7"
          ],
          "defaultStatus": "unaffected",
          "packageName": "389-ds-base",
          "product": "Red Hat Enterprise Linux 7",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:8"
          ],
          "defaultStatus": "unaffected",
          "packageName": "389-ds:1.4/389-ds-base",
          "product": "Red Hat Enterprise Linux 8",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:9"
          ],
          "defaultStatus": "unaffected",
          "packageName": "389-ds-base",
          "product": "Red Hat Enterprise Linux 9",
          "vendor": "Red Hat"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Red Hat would like to thank Adam Korczynski (Ada Logics), Arthur Chan (Ada Logics), David Korczynski (Ada Logics), and Team (Anthropic) for reporting this issue."
        }
      ],
      "datePublic": "2026-08-12T07:21:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "A flaw was found in 389-ds-base. The get_ldapmessage_controls_ext() function frees the parsed controls array on the Session Tracking critical-control rejection path without clearing the SLAPI_REQCONTROLS pblock slot. Operation teardown then frees the same pointer again, causing a double-free. An unauthenticated remote attacker can trigger this with a single BIND request carrying a critical Session Tracking control, resulting in heap corruption and potential denial of service."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "namespace": "https://access.redhat.com/security/updates/classification/",
              "value": "Moderate"
            },
            "type": "Red Hat severity rating"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-415",
              "description": "Double Free",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-12T09:35:26.681Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2026-18663"
        },
        {
          "name": "RHBZ#2510631",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2510631"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-07-08T00:00:00.000Z",
          "value": "Reported to Red Hat."
        },
        {
          "lang": "en",
          "time": "2026-08-12T07:21:00.000Z",
          "value": "Made public."
        }
      ],
      "title": "389-ds-base: 389-ds-base: pre-authentication double-free in get_ldapmessage_controls_ext() via critical session tracking control",
      "workarounds": [
        {
          "lang": "en",
          "value": "On builds that include upstream Issue 7389 (committed 2026-04-09, present in 389-ds-base-3.2 branch), administrators can add the Session Tracking control OID (1.3.6.1.4.1.21008.108.63.1) to the ds-ignored-control-criticality configuration attribute. This causes the server to ignore the criticality flag on this control, preventing the vulnerable rejection path from being reached.\n\nAdditionally, network-level restriction of access to the LDAP port (389/636) to trusted clients reduces exposure."
        }
      ],
      "x_generator": {
        "engine": "cvelib 1.8.0"
      },
      "x_redhatCweChain": "CWE-415: Double Free"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2026-18663",
    "datePublished": "2026-08-12T09:35:26.681Z",
    "dateReserved": "2026-08-03T13:22:45.359Z",
    "dateUpdated": "2026-08-13T15:41:09.335Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-18663",
      "date": "2026-09-22",
      "epss": "0.00432",
      "percentile": "0.36961"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/a:redhat:directory_server:11"
                ],
                "defaultStatus": "unaffected",
                "packageName": "redhat-ds:11/389-ds-base",
                "product": "Red Hat Directory Server 11",
                "vendor": "Red Hat"
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/a:redhat:directory_server:12"
                ],
                "defaultStatus": "unaffected",
                "packageName": "redhat-ds:12/389-ds-base",
                "product": "Red Hat Directory Server 12",
                "vendor": "Red Hat"
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/a:redhat:directory_server:13"
                ],
                "defaultStatus": "affected",
                "packageName": "389-ds-base",
                "product": "Red Hat Directory Server 13",
                "vendor": "Red Hat"
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/o:redhat:enterprise_linux:10"
                ],
                "defaultStatus": "affected",
                "packageName": "389-ds-base",
                "product": "Red Hat Enterprise Linux 10",
                "vendor": "Red Hat"
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/o:redhat:enterprise_linux:6"
                ],
                "defaultStatus": "unaffected",
                "packageName": "389-ds-base",
                "product": "Red Hat Enterprise Linux 6",
                "vendor": "Red Hat"
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/o:redhat:enterprise_linux:7"
                ],
                "defaultStatus": "unaffected",
                "packageName": "389-ds-base",
                "product": "Red Hat Enterprise Linux 7",
                "vendor": "Red Hat"
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/o:redhat:enterprise_linux:8"
                ],
                "defaultStatus": "unaffected",
                "packageName": "389-ds:1.4/389-ds-base",
                "product": "Red Hat Enterprise Linux 8",
                "vendor": "Red Hat"
              },
              {
                "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
                "cpes": [
                  "cpe:/o:redhat:enterprise_linux:9"
                ],
                "defaultStatus": "unaffected",
                "packageName": "389-ds-base",
                "product": "Red Hat Enterprise Linux 9",
                "vendor": "Red Hat"
              }
            ],
            "source": "secalert@redhat.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "A flaw was found in 389-ds-base. The get_ldapmessage_controls_ext() function frees the parsed controls array on the Session Tracking critical-control rejection path without clearing the SLAPI_REQCONTROLS pblock slot. Operation teardown then frees the same pointer again, causing a double-free. An unauthenticated remote attacker can trigger this with a single BIND request carrying a critical Session Tracking control, resulting in heap corruption and potential denial of service."
          }
        ],
        "id": "CVE-2026-18663",
        "lastModified": "2026-08-14T19:07:46.080",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 5.9,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 2.2,
              "impactScore": 3.6,
              "source": "secalert@redhat.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-18663",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-13T15:40:56.481579Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-08-12T10:17:18.437",
        "references": [
          {
            "source": "secalert@redhat.com",
            "url": "https://access.redhat.com/security/cve/CVE-2026-18663"
          },
          {
            "source": "secalert@redhat.com",
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2510631"
          }
        ],
        "sourceIdentifier": "secalert@redhat.com",
        "vulnStatus": "Awaiting Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-415"
              }
            ],
            "source": "secalert@redhat.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-13T03:12:56+00:00",
      "cve": "CVE-2026-18663",
      "id": "CVE-2026-18663",
      "initial_release_date": "2026-08-12T07:21:00+00:00",
      "product_status:known_affected": "8",
      "product_status:known_not_affected": "25",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "389-ds-base: 389-ds-base: pre-authentication double-free in get_ldapmessage_controls_ext() via critical Session Tracking control",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-18663.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-18T00:17:35Z",
      "cve": "CVE-2026-18663",
      "id": "CVE-2026-18663",
      "initial_release_date": "2026-08-18T00:17:35Z",
      "product_status:known_affected": "108",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-18663",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-18663.json",
      "version": "2"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-18663",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-08-13T15:40:56.481579Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-08-13T15:41:04.688Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
              "cpes": [
                "cpe:/a:redhat:directory_server:11"
              ],
              "defaultStatus": "unaffected",
              "packageName": "redhat-ds:11/389-ds-base",
              "product": "Red Hat Directory Server 11",
              "vendor": "Red Hat"
            },
            {
              "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
              "cpes": [
                "cpe:/a:redhat:directory_server:12"
              ],
              "defaultStatus": "unaffected",
              "packageName": "redhat-ds:12/389-ds-base",
              "product": "Red Hat Directory Server 12",
              "vendor": "Red Hat"
            },
            {
              "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
              "cpes": [
                "cpe:/a:redhat:directory_server:13"
              ],
              "defaultStatus": "affected",
              "packageName": "389-ds-base",
              "product": "Red Hat Directory Server 13",
              "vendor": "Red Hat"
            },
            {
              "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
              "cpes": [
                "cpe:/o:redhat:enterprise_linux:10"
              ],
              "defaultStatus": "affected",
              "packageName": "389-ds-base",
              "product": "Red Hat Enterprise Linux 10",
              "vendor": "Red Hat"
            },
            {
              "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
              "cpes": [
                "cpe:/o:redhat:enterprise_linux:6"
              ],
              "defaultStatus": "unaffected",
              "packageName": "389-ds-base",
              "product": "Red Hat Enterprise Linux 6",
              "vendor": "Red Hat"
            },
            {
              "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
              "cpes": [
                "cpe:/o:redhat:enterprise_linux:7"
              ],
              "defaultStatus": "unaffected",
              "packageName": "389-ds-base",
              "product": "Red Hat Enterprise Linux 7",
              "vendor": "Red Hat"
            },
            {
              "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
              "cpes": [
                "cpe:/o:redhat:enterprise_linux:8"
              ],
              "defaultStatus": "unaffected",
              "packageName": "389-ds:1.4/389-ds-base",
              "product": "Red Hat Enterprise Linux 8",
              "vendor": "Red Hat"
            },
            {
              "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
              "cpes": [
                "cpe:/o:redhat:enterprise_linux:9"
              ],
              "defaultStatus": "unaffected",
              "packageName": "389-ds-base",
              "product": "Red Hat Enterprise Linux 9",
              "vendor": "Red Hat"
            }
          ],
          "credits": [
            {
              "lang": "en",
              "value": "Red Hat would like to thank Adam Korczynski (Ada Logics), Arthur Chan (Ada Logics), David Korczynski (Ada Logics), and Team (Anthropic) for reporting this issue."
            }
          ],
          "datePublic": "2026-08-12T07:21:00.000Z",
          "descriptions": [
            {
              "lang": "en",
              "value": "A flaw was found in 389-ds-base. The get_ldapmessage_controls_ext() function frees the parsed controls array on the Session Tracking critical-control rejection path without clearing the SLAPI_REQCONTROLS pblock slot. Operation teardown then frees the same pointer again, causing a double-free. An unauthenticated remote attacker can trigger this with a single BIND request carrying a critical Session Tracking control, resulting in heap corruption and potential denial of service."
            }
          ],
          "metrics": [
            {
              "other": {
                "content": {
                  "namespace": "https://access.redhat.com/security/updates/classification/",
                  "value": "Moderate"
                },
                "type": "Red Hat severity rating"
              }
            },
            {
              "cvssV3_1": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 5.9,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "format": "CVSS"
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-415",
                  "description": "Double Free",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-12T09:35:26.681Z",
            "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
            "shortName": "redhat"
          },
          "references": [
            {
              "tags": [
                "vdb-entry",
                "x_refsource_REDHAT"
              ],
              "url": "https://access.redhat.com/security/cve/CVE-2026-18663"
            },
            {
              "name": "RHBZ#2510631",
              "tags": [
                "issue-tracking",
                "x_refsource_REDHAT"
              ],
              "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2510631"
            }
          ],
          "timeline": [
            {
              "lang": "en",
              "time": "2026-07-08T00:00:00.000Z",
              "value": "Reported to Red Hat."
            },
            {
              "lang": "en",
              "time": "2026-08-12T07:21:00.000Z",
              "value": "Made public."
            }
          ],
          "title": "389-ds-base: 389-ds-base: pre-authentication double-free in get_ldapmessage_controls_ext() via critical session tracking control",
          "workarounds": [
            {
              "lang": "en",
              "value": "On builds that include upstream Issue 7389 (committed 2026-04-09, present in 389-ds-base-3.2 branch), administrators can add the Session Tracking control OID (1.3.6.1.4.1.21008.108.63.1) to the ds-ignored-control-criticality configuration attribute. This causes the server to ignore the criticality flag on this control, preventing the vulnerable rejection path from being reached.\n\nAdditionally, network-level restriction of access to the LDAP port (389/636) to trusted clients reduces exposure."
            }
          ],
          "x_generator": {
            "engine": "cvelib 1.8.0"
          },
          "x_redhatCweChain": "CWE-415: Double Free"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "assignerShortName": "redhat",
        "cveId": "CVE-2026-18663",
        "datePublished": "2026-08-12T09:35:26.681Z",
        "dateReserved": "2026-08-03T13:22:45.359Z",
        "dateUpdated": "2026-08-13T15:41:09.335Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



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.