How severe is CVE-2021-27212?

CVE-2021-27212 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-27212 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 64% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27212?

CVE-2021-27212 primarily affects Openldap. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-27212?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-27212 published?

CVE-2021-27212 was published on 2021-02-14 and last updated on 2026-06-17.

CVE-2021-27212

CVE-2021-27212 is a high-severity vulnerability in Openldap with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 64% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-617.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 64% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-617
Affected product: Openldap
Published: 2021-02-14
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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, resulting in a denial of service (daemon exit) via a short timestamp. This is related to schema_init.c and checkTime.
How severe is CVE-2021-27212?: CVE-2021-27212 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-27212 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 64% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27212?: CVE-2021-27212 primarily affects Openldap. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-27212?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27212 published?: CVE-2021-27212 was published on 2021-02-14 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:openldap:openldap:*:*:*:*:*:*:*:*
cpe:2.3:a:openldap:openldap:2.5.0:alpha:*:*:*:*:*:*
cpe:2.3:a:openldap:openldap:2.5.1:alpha:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

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