CVE-2026-103877: Deserialization of Untrusted Data vulnerability in Apache Directory LDAP API. A rogue/compromised LDAP serv

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CRITICAL 9.8REMOTEWATCHLIST

CVE-2026-103877 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-10-02
Last modified	2026-10-07

Publisher (CNA): Apache Software Foundation

Last updated 2026-10-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-10-02 10:17 UTCPublished CVE record published
2026-10-07 23:16 UTCUpdated Record last modified

Exact fixes by distribution

Fedora ELN · edk2 · FIXED · 20260812-12.eln159 · FEDORA-2026-e316b6370a · source

sudo dnf upgrade --advisory=FEDORA-2026-e316b6370a

Fedora 46 · perl-Mojo-DOM58 · FIXED · 3.003-1.fc46 · FEDORA-2026-d5412af3de · source

sudo dnf upgrade --advisory=FEDORA-2026-d5412af3de

Debian 12 · apache-directory-api · NO FIX YET

Debian 13 · apache-directory-api · NO FIX YET

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-103877?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-103877 being exploited?

CVE-2026-103877 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-103877 affect?

CVE-2026-103877 affects affected software. Severity is critical (CVSS 9.8). 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 clas

How urgent is CVE-2026-103877?

Priority 57/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Java vulnerabilities

References

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