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Findings

CVE-2020-36221

An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial of service (s…

Published Jan 26, 2021 · updated Oct 14, 2026 · openldap openldap

An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial of service (schema_init.c serialNumberAndIssuerCheck).

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 26, 2021 · NIST NVD

    Detected

    An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial of service (schema_init.c serialNumberAndIssuerCheck).

  2. Oct 14, 2026 · NIST NVD

    Updated

    An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial of service (schema_init.c serialNumberAndIssuerCheck).

Affected

  • cpe apple/mac os xversion unspecified
  • cpe apple/mac os x10.14.6
  • cpe debian/debian linux10.0
  • cpe debian/debian linux9.0
  • cpe openldap/openldapversion unspecified

Sources

  • CVE.orgVulnerability recordCVE-2020-36221

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2020-36221

    30-day exploitation probability 85.0%

    first.org
  • NIST NVDVulnerability recordCVE-2020-36221

    An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial of service (schema_init.c serialNumberAndIssuerCheck).

    nvd.nist.gov

References

CVE-2020-36221 · ZeroDay Findings