---
id: CVE-2026-103877
title: >-
  Deserialization of Untrusted Data vulnerability in Apache Directory LDAP API.




  A rogue/compromised LDAP server (or pre-TLS MITM) can answer a client's
  loadSchema() subschema search with a schema object that contains a serialized
  Java c…
summary: >-
  Deserialization of Untrusted Data vulnerability in Apache Directory LDAP API.




  A rogue/compromised LDAP server (or pre-TLS MITM) can answer a client's
  loadSchema() subschema search with a schema object that contains a serialized
  Java c…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-502
vendor: Apache Software Foundation
product: 'org.apache.directory.api:api-ldap-schema-data'
affected:
  - 'org.apache.directory.api:api-ldap-schema-data >= 2.1.0 < 2.1.9'
published: '2026-10-02'
updated: '2026-10-07'
sourceUpdated: '2026-10-07T23:16:58.850'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-103877'
references:
  - url: 'https://lists.apache.org/thread.html/sys8l881blqfgoc3o724jl32bmjl8pvw'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/10/02/5'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-103877.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-103877'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2544997'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-103877'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-103877'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00469
epssPercentile: 0.40435
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-07T20:54:06.776749Z'
scores:
  nvd: 9.8
  vendor: 8.1
  adp: 9.8
ingestedAt: '2026-10-02T10:15:55.897Z'
---

## Overview

Deserialization of Untrusted Data vulnerability in Apache Directory LDAP API.



A rogue/compromised LDAP server (or pre-TLS MITM) can answer a client's loadSchema() subschema search with a schema object that contains a serialized Java class, allowing some potential RCE. 



This issue affects Apache Directory LDAP API: from 2.1.0 before 2.1.9.



Users are recommended to upgrade to version 2.1.9, which fixes the issue.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Fuse 7 · no fix planned: Red Hat Fuse 7 · updated 2026-10-02 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-103877.json)