HOMEVULNERABILITIESCVE-2021-27212
HIGH

CVE-2021-27212

CWE-617Published: February 14, 2021· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-27212 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
openldap1 product(s)
openldap
Source: NVD CPE · 5 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://git.openldap.org/openldap/openldap/-/commit/3539fc33212b528c56b716584f2c2994af7c30b0
PATCHhttps://git.openldap.org/openldap/openldap/-/commit/9badb73425a67768c09bcaed1a9c26c684af6c30
PATCHhttps://git.openldap.org/openldap/openldap/-/commit/3539fc33212b528c56b716584f2c2994af7c30b0
PATCHhttps://git.openldap.org/openldap/openldap/-/commit/9badb73425a67768c09bcaed1a9c26c684af6c30
ADVISORYhttps://bugs.openldap.org/show_bug.cgi?id=9454
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/02/msg00035.html
ADVISORYhttps://security.netapp.com/advisory/ntap-20210319-0005/
ADVISORYhttps://www.debian.org/security/2021/dsa-4860
ADVISORYhttps://bugs.openldap.org/show_bug.cgi?id=9454
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/02/msg00035.html
ADVISORYhttps://security.netapp.com/advisory/ntap-20210319-0005/
ADVISORYhttps://www.debian.org/security/2021/dsa-4860

All References (16)

→
https://bugs.openldap.org/show_bug.cgi?id=9454Exploit · Issue Tracking · Vendor Advisory
→
https://git.openldap.org/openldap/openldap/-/commit/3539fc33212b528c56b716584f2c2994af7c30b0Patch · Vendor Advisory
→
https://git.openldap.org/openldap/openldap/-/commit/9badb73425a67768c09bcaed1a9c26c684af6c30Patch · Vendor Advisory
→
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
→
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
→
https://lists.debian.org/debian-lts-announce/2021/02/msg00035.htmlMailing List · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210319-0005/Third Party Advisory
→
https://www.debian.org/security/2021/dsa-4860Third Party Advisory
→
https://bugs.openldap.org/show_bug.cgi?id=9454Exploit · Issue Tracking · Vendor Advisory
→
https://git.openldap.org/openldap/openldap/-/commit/3539fc33212b528c56b716584f2c2994af7c30b0Patch · Vendor Advisory
→
https://git.openldap.org/openldap/openldap/-/commit/9badb73425a67768c09bcaed1a9c26c684af6c30Patch · Vendor Advisory
→
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
→
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
→
https://lists.debian.org/debian-lts-announce/2021/02/msg00035.htmlMailing List · Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210319-0005/Third Party Advisory

Quick Facts

CVE IDCVE-2021-27212
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-617
CISA KEVNo
Affected2 vendor(s)
PublishedFeb 14, 2021

Related CVEs (CWE-617)

CVE-2020-3615
9.8
CVE-2019-9795
9.8
CVE-2020-12417
8.8
CVE-2020-6623
8.8
CVE-2020-6619
8.8
CVE-2020-6617
8.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-27212 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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