---
title: "CVE-2020-36221: An integer underflow was discovered… | CubePath"
description: "An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial…"
language: en
source: https://cubepath.com/security/cve/CVE-2020-36221
---

# CVE-2020-36221: An integer underflow was discovered… | CubePath

## Description

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).

Official description from the CVE record, published by mitre. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2020-36221)

## Key data

### EPSS

Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days.

Score

0.84994 (85.0% probability)

Percentile

99.7%

Scores of

Nov 10, 2026

Model

v2026.06.15

## References

Links listed in the CVE record. They lead to other sites, which CubePath does not control.

- [bugs.openldap.org/show\_bug.cgi?id=9404](https://bugs.openldap.org/show%5Fbug.cgi?id=9404)
- [git.openldap.org/openldap/openldap/-/commit/38ac838e4150c62…](https://git.openldap.org/openldap/openldap/-/commit/38ac838e4150c626bbfa0082b7e2cf3a2bb4df31)
- [bugs.openldap.org/show\_bug.cgi?id=9424](https://bugs.openldap.org/show%5Fbug.cgi?id=9424)
- [git.openldap.org/openldap/openldap/-/commit/58c1748e81c843c…](https://git.openldap.org/openldap/openldap/-/commit/58c1748e81c843c5b6e61648d2a4d1d82b47e842)
- [git.openldap.org/openldap/openldap/-/tags/OPENLDAP\_REL\_ENG\_…](https://git.openldap.org/openldap/openldap/-/tags/OPENLDAP%5FREL%5FENG%5F2%5F4%5F57)
- [\[debian-lts-announce\] 20210203 \[SECURITY\] \[DLA 2544-1\] openldap security update](https://lists.debian.org/debian-lts-announce/2021/02/msg00005.html)  (lists.debian.org) mailing-list
- [DSA-4845](https://www.debian.org/security/2021/dsa-4845)  (debian.org) vendor-advisory
- [security.netapp.com/advisory/ntap-20210226-0002](https://security.netapp.com/advisory/ntap-20210226-0002/)
- [support.apple.com/kb/HT212529](https://support.apple.com/kb/HT212529)
- [support.apple.com/kb/HT212531](https://support.apple.com/kb/HT212531)
- [support.apple.com/kb/HT212530](https://support.apple.com/kb/HT212530)
- [20210526 APPLE-SA-2021-05-25-2 macOS Big Sur 11.4](http://seclists.org/fulldisclosure/2021/May/70)  (seclists.org) mailing-list
- [20210526 APPLE-SA-2021-05-25-4 Security Update 2021-003 Catalina](http://seclists.org/fulldisclosure/2021/May/64)  (seclists.org) mailing-list
- [20210526 APPLE-SA-2021-05-25-3 Security Update 2021-004 Mojave](http://seclists.org/fulldisclosure/2021/May/65)  (seclists.org) mailing-list
- [\[bookkeeper-issues\] 20210628 \[GitHub\] \[bookkeeper\] padma81 opened a new issue #2746: Security Vulnerabilities in CentOS 7 image, Upgrade image to CentOS 8](https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E)  (lists.apache.org) mailing-list
- [\[bookkeeper-issues\] 20210629 \[GitHub\] \[bookkeeper\] padma81 opened a new issue #2746: Security Vulnerabilities in CentOS 7 image, Upgrade image to CentOS 8](https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E)  (lists.apache.org) mailing-list

## Timeline

1. ID reserved Jan 25, 2021
2. Record published Jan 25, 2021
3. Record last updated Oct 14, 2026

## Look up another CVE

## About CubePath

CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection.

[Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection)

Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 20:03 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)