Skip to main content
No exploitation reportedFix available

CVE-2021-27212

No exploitation reported by the sources we read.

  • Published2021-02-14
  • WeaknessCWE-617

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-02-1403:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-27212?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-27212?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Openldap
BranchAffectedFixed in
2.4≤ 2.4.57no fix published
2.5= 2.5.0no fix published
2.5= 2.5.1no fix published
openldap
BranchAffectedFixed in
2.4< 2.4.582.4.58
Debian debian linux
BranchAffectedFixed in
10.0= 10.0no fix published
9.0= 9.0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • openldapUbuntu:Pro:14.04:LTSall versions · fixed in 2.4.31-1+nmu2ubuntu8.5+esm8
  • openldapUbuntu:20.04:LTSall versions · fixed in 2.4.49+dfsg-2ubuntu1.7
  • openldapUbuntu:18.04:LTSall versions · fixed in 2.4.45+dfsg-1ubuntu1.10
  • openldapUbuntu:16.04:LTSall versions · fixed in 2.4.42+dfsg-2ubuntu3.13
  • openldapTuxCare:RHEL:7all versions · fixed in 2.4.44-25.el7_9.tuxcare.els1and 4 other packages
  • openldapTuxCare:OracleLinux:7all versions · fixed in 2.4.44-25.el7_9.tuxcare.els1and 4 other packages
  • openldapTuxCare:OracleLinux:6all versions · fixed in 2.4.40-16.el6.tuxcare.els1and 4 other packages
  • openldapTuxCare:CentOS:8.4all versions · fixed in 2.4.46-17.el8_4.tuxcare.els1and 3 other packages

68 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-27212 Red Hat Product Security14 known affected

    openldap: Assertion failure in slapd in the issuerAndThisUpdateCheck function

    compat-openldap as a component of Red Hat Enterprise Linux 6 · openldap as a component of Red Hat Enterprise Linux 6 · openldap-clients as a component of Red Hat Enterprise Linux 6 · +11 more

  • ICSA-23-348-10 CISA5 known affected

    Siemens SIMATIC S7-1500

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) · +2 more

  • SSA-398330 Siemens ProductCERT5 known affected

    SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.0 < V3.1.5 · +2 more

Full record on NVD

Fix

  1. Vendor fix CISA ICSA-23-348-10 · 5 productsUpdate to V3.1.5 or later version
  2. Vendor fix Siemens ProductCERT SSA-398330 · 1 productUpdate to V3.1.5 or later version
  3. Mitigation from the vendor CISA ICSA-23-348-10 · 5 productsOnly build and run applications from trusted sources.
  4. No fix planned, says the vendor Red Hat Product Security CVE-2021-27212 · 8 productsOut of support scope
  5. No fix planned, says the vendor Red Hat Product Security CVE-2021-27212 · 6 productsWill not fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2021-02-14
Last Modified
2026-10-14
NVD status
Modified
GitHub Advisory
GHSA-274h-c788-hf3c

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.

Is CVE-2021-27212 actively exploited?

Active exploitation of CVE-2021-27212 has not been confirmed. Its EPSS score was 66.1% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-27212?

CVE-2021-27212 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Running openldap? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, November 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database

Sources for this record