---
title: "CVE-2026-103877: Apache Directory LDAP API - Insecure Deserialization"
description: "Apache Directory LDAP API >= 2.1.0 < 2.1.9 contains an insecure deserialization vulnerability caused by processing serialized Java classes in schema objects from untrusted LDAP servers, letting attackers achieve potential remote code execution, exploit requires a rogue or compromised LDAP server or pre-TLS man-in-the-middle."
url: https://panop.io/threat-heartbeat/CVE-2026-103877/
---

# CVE-2026-103877 Apache Directory LDAP API - Insecure Deserialization

Apache Directory LDAP API >= 2.1.0 < 2.1.9 contains an insecure deserialization vulnerability caused by processing serialized Java classes in schema objects from untrusted LDAP servers, letting attackers achieve potential remote code execution, exploit requires a rogue or compromised LDAP server or pre-TLS man-in-the-middle.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

EPSS

0.57% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-103877)

## Details

Type

Insecure Deserialization

Impact

Remote Code Execution

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Published

2 October 2026

Updated

15 October 2026

Weakness

[CWE-502](https://cwe.mitre.org/data/definitions/502.html)

## Vendor fix

Upgrade to version 2.1.9.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-103877](https://nvd.nist.gov/vuln/detail/CVE-2026-103877)
- [https://lists.apache.org/thread.html/sys8l881blqfgoc3o724jl32bmjl8pvw](https://lists.apache.org/thread.html/sys8l881blqfgoc3o724jl32bmjl8pvw)
- [http://www.openwall.com/lists/oss-security/2026/10/02/5](http://www.openwall.com/lists/oss-security/2026/10/02/5)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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