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No exploitation reported

CVE-2026-103877

Apache Directory LDAP API: Unsafe loading of Java code from LDAP schema elements

No exploitation reported by the sources we read.

  • Published2026-10-02
  • WeaknessCWE-502

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-10-0210:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-103877?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-103877?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-103877 Red Hat Product Security

    org.apache.directory.api/api-ldap-client-api: Apache Directory LDAP API: Remote code execution via untrusted Java object deserialization

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2026-10-02
Last Modified
2026-10-07
NVD status
Deferred

Frequently asked questions

What is CVE-2026-103877?

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.

Is CVE-2026-103877 actively exploited?

Active exploitation of CVE-2026-103877 has not been confirmed. Its EPSS score was 0.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-103877?

CVE-2026-103877 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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