CVE Intelligence
High Denial of service exploit reference

CVE-2020-12243 — In filter.c in slapd in OpenLDAP before 2.4.50, LDAP search filters with nested boolean...

In filter.c in slapd in OpenLDAP before 2.4.50, LDAP search filters with nested boolean expressions can result in denial of service (daemon crash).

Published Apr 28, 2020 · Updated Oct 14, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: mitre

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 4.7% (30-day exploitation probability)+14
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
4.72%
ahead of 92% of scored CVEs · Oct 15, 2026
Affects
Apple
Mac Os X and 17 more
CVSS base
7.5
High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Apple Mac Os X, Broadcom Brocade Fabric Operating System, Canonical Ubuntu Linux…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. EPSS ahead of 92% of scored CVEs: prioritize it in the patch queue.
  5. Search available logs for exploit probes matching the vulnerability class (denial of service), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Apple Mac Os X version 10.13.6-security_update_2019-007≥ 10.14.0 and < 10.14.6≥ 10.15 and < 10.15.6version 10.13.6-security_update_2018-002version 10.13.6-security_update_2018-003version 10.13.6-security_update_2019-001version 10.13.6-security_update_2019-002version 10.13.6-security_update_2019-003
and 26 more version 10.13.6-security_update_2019-004version 10.13.6-security_update_2019-005version 10.13.6-security_update_2019-006≥ 10.13.0 and < 10.13.6version 10.13.6-security_update_2020-001version 10.13.6-security_update_2020-002version 10.13.6-security_update_2020-003version 10.13.6-supplemental_updateversion 10.14.6-security_update_2019-001version 10.14.6-security_update_2019-002version 10.14.6-security_update_2019-004version 10.14.6-security_update_2019-005version 10.14.6-security_update_2019-006version 10.14.6-security_update_2019-007version 10.14.6-supplemental_update_2version 10.14.6-supplemental_updateversion 10.14.6-security_update_2021-003version 10.14.6-security_update_2021-002version 10.14.6-security_update_2021-001version 10.14.6-security_update_2020-007version 10.14.6-security_update_2020-006version 10.14.6-security_update_2020-005version 10.14.6-security_update_2020-004version 10.14.6-security_update_2020-003version 10.14.6-security_update_2020-002version 10.14.6-security_update_2020-001
Vulnerable NIST National Vulnerability Database
Broadcom Brocade Fabric Operating System versions not specified by the source Vulnerable NIST National Vulnerability Database
Canonical Ubuntu Linux version 20.04version 19.10version 18.04version 16.04version 14.04version 12.04 Vulnerable NIST National Vulnerability Database
Debian Debian Linux version 9.0version 8.0version 10.0 Vulnerable NIST National Vulnerability Database
Netapp Cloud Backup versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H300e Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H300s Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H410c Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H410s Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H500e Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H500s Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H700e Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp H700s Firmware versions not specified by the source Vulnerable NIST National Vulnerability Database
Netapp Steelstore Cloud Integrated Storage versions not specified by the source Vulnerable NIST National Vulnerability Database
Openldap OpenLDAP < 2.4.50 Vulnerable NIST National Vulnerability Database
Opensuse Leap version 15.1 Vulnerable NIST National Vulnerability Database
Oracle Solaris version 11version 10 Vulnerable NIST National Vulnerability Database
Oracle Zfs Storage Appliance Kit version 8.8 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.1 High 3.9 3.6 nvd@nist.gov via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
5.0 CVSS 2.0 Medium 10.0 2.9 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-674 · Uncontrolled Recursion

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 4.72%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Track CPU/memory spikes and availability drops correlated with request patterns.
web/proxy/WAF logsnetwork IDS/IPSresource metrics

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 14, 2026
  • Fix documented
    Oct 14, 2026 · NIST National Vulnerability Database
  • Affected products added · openldap/openldap, debian/debian linux, opensuse/leap, canonical/ubuntu linux, netapp/cloud backup, netapp/steelstore cl
    Oct 14, 2026 · NIST National Vulnerability Database
  • CVSS changed · 7.5
    Oct 14, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 14, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 14, 2026 · Alertas do Telegram
  • 2020
  • CVE published
    Apr 28, 2020 · mitre

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 14, 2026 – Oct 14, 2026
  • 1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

18 on the record

Elsewhere on this site

Apple
every CVE for this vendor
Denial of service
same class
CWE-674
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
  • CVE-2026-61202 Improper Access Control in Oracle Solaris Jul 21, 2026
  • CVE-2026-61052 Uncontrolled Resource Consumption in Oracle Solaris Jul 21, 2026
  • CVE-2026-60834 Improper Access Control in Oracle Solaris Jul 21, 2026
  • CVE-2026-60833 Improper Privilege Management in Oracle Solaris Jul 21, 2026
  • CVE-2026-60661 Improper Privilege Management in Oracle Solaris Jul 21, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2020-12243 is "In filter.c in slapd in OpenLDAP before 2.4.50, LDAP search filters with nested boolean...", rated High. It affects Mac Os X (Apple); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 4.72% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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