CVE Intelligence
Medium

CVE-2026-78359 — Duplicate Identity / Identity Shadowing across CustomerUser backends

OTRS does not sufficiently enforce the uniqueness of customer user identities across multiple configured CustomerUser backends. When multiple backends, such as a database and LDAP, are configured, the uniqueness check for customer user email addresses is performed only within the selected backend. As a result, an authenticated user with permission to create or modify customer users may create a customer user whose email address is already assigned to a customer user in another backend. This can result in multiple customer user records representing the same communication identity. Depending on the affected workflow and backend resolution, customer-related information or email communication may subsequently be associated with or exposed to the wrong customer user. The vulnerability does not allow unauthenticated users to create customer accounts. Exploitation requires permissions to create or modify customer users. This issue affects OTRS: * 7.0.X * 8.0.X * 2023.X * 2024.X * 2025.X * 2026.X before 2026.7.X Please note that ((OTRS)) Community Edition 6.x and before are vulnerable. Products based on the ((OTRS)) Community Edition also very likely to be affected

Published Oct 12, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: OTRS

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.16%
ahead of 5% of scored CVEs · Oct 15, 2026
Affects
OTRS GmbH (former OTRS AG)
((OTRS)) Community Edition and 1 more
CVSS base
5.4
Medium · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (OTRS GmbH (former OTRS AG) ((OTRS)) Community Edition, OTRS GmbH (former OTRS AG) OTRS).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
OTRS GmbH (former OTRS AG) ((OTRS)) Community Edition version 6.x Vulnerable CVE Program (cve.org) e CISA ADP
OTRS GmbH (former OTRS AG) OTRS version 7.0.xversion 8.0.xversion 2023.xversion 2024.xversion 2025.x≥ 2026.x and ≤ 2026.6.x Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
5.4 CVSS 3.1 Medium 2.8 2.5 security@otrs.com via NIST National Vulnerability Database
5.4 CVSS 3.1 Medium — — GitHub, Inc. via GitHub Security Advisories
5.4 CVSS 3.1 Medium — — OTRS via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N (score shown at the top: security@otrs.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-694

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.16%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · Received → Deferred
    Oct 15, 2026 · NIST National Vulnerability Database
  • Affected products added · otrs gmbh (former otrs ag)/otrs, otrs gmbh (former otrs ag)/((otrs)) community edition
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 5.4
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Oct 12, 2026 · OTRS

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 15, 2026 – Oct 15, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

Elsewhere on this site

OTRS GmbH (former OTRS AG)
every CVE for this vendor
CWE-694
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-78357 Insufficient Session Revocation for JWT Authentication 4d
  • CVE-2026-93581 Insufficient Neutralization of Formula Elements in CSV Exports 4d
  • CVE-2026-78358 Cross-Site Request Forgery in Administrative Actions 4d
  • CVE-2026-93582 Authentication Bypass via Spoofed Remote-User Header in HTTP Basic Authentication 4d
  • CVE-2026-48211 Cross-Site Request Forgery in Import/Export Admin console 4d
  • CVE-2026-48212 Stored XSS in external pages 4d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-78359 is "Duplicate Identity / Identity Shadowing across CustomerUser backends", rated Medium. It affects ((OTRS)) Community Edition (OTRS GmbH (former OTRS AG)); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.4 describes technical severity. EPSS 0.16% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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