---
id: CVE-2026-22185
title: OpenLDAP LMDB mdb_load Heap Buffer Underflow in readline()
summary: >-
  OpenLDAP Lightning Memory-Mapped Database (LMDB) versions 0.9.14 before
  0.9.34, prior to commit 8e1fda8, contain a heap buffer underflow in the
  readline() function of mdb_load. When processing malformed input containing an
  embedded NUL b…
severity: medium
cvss: 4.6
cvssVector: 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-125
  - CWE-191
vendor: OpenLDAP Foundation
product: OpenLDAP
affected:
  - OpenLDAP >= 0.9.14 < 0.9.34
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-01-07T21:25:36.753538Z'
exploitAvailable: true
published: '2026-01-07'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T21:15:35.807Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-22185'
references:
  - url: 'https://seclists.org/fulldisclosure/2026/Jan/5'
  - url: 'https://seclists.org/fulldisclosure/2026/Jan/8'
  - url: 'https://www.openldap.org/'
  - url: >-
      https://www.vulncheck.com/advisories/openldap-lmdb-mdb-load-heap-buffer-underflow-in-readline
  - url: 'https://bugs.openldap.org/show_bug.cgi?id=10421'
tags:
  - cve.org
  - exploit-available
epss: 0.00152
epssPercentile: 0.0437
ingestedAt: '2026-11-03T08:39:35.547Z'
---

## Overview

OpenLDAP Lightning Memory-Mapped Database (LMDB) versions 0.9.14 before 0.9.34, prior to commit 8e1fda8, contain a heap buffer underflow in the readline() function of mdb_load. When processing malformed input containing an embedded NUL byte, an unsigned offset calculation can underflow and cause an out-of-bounds read of one byte before the allocated heap buffer. This can cause mdb_load to crash, leading to a limited denial-of-service condition.

## Affected

- `OpenLDAP >= 0.9.14 < 0.9.34`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.