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Vulnerabilities

Vulnerability · 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 via a crafted packet, resulti…

Published Feb 14, 2021 · catalog updated Oct 14, 2026 · the affected product

Check this week

CVE-2021-27212 is not in CISA KEV. FIRST estimates a 66.11% chance of exploitation in the next 30 days. Check whether you run the affected product.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
66.11%
Remediation
Advisory link
Affected products
cpe debian/debian linux · cpe openldap/openldap

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe debian/debian linux10.0
  • cpe debian/debian linux9.0
  • cpe openldap/openldap2.5.0
  • cpe openldap/openldap2.5.1

How to fix CVE-2021-27212

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-27212 is not in CISA KEV. FIRST estimates a 66.11% chance of exploitation in the next 30 days. Check whether you run the affected product.

Which versions are affected?

Compare what you have installed with debian/debian linux 10.0; debian/debian linux 9.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-617. EPSS 66.11%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

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. Feb 14, 2021 · NIST NVD

    Detected

    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.

  2. Oct 14, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2021-27212

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-27212

    30-day exploitation probability 66.11%

    first.org
  • NIST NVDVulnerability recordCVE-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 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.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 24, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.