Security Resilience

CVE-2023-25160

Access Control in Nextcloud Mail ≤ 1.11.8

Access Control
Published
13 February 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 4.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:N/A:N
EPSS Score 0.0046 38th percentile
Risk Priority 34 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-25160 is a medium-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Nextcloud Mail. Its CVSS base score is 4.1 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked at the 38th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

Nextcloud Mail is an email app for the Nextcloud home server platform. Prior to versions 2.2.1, 1.14.5, 1.12.9, and 1.11.8, an attacker can access the mail box by ID getting the subjects and the first characters of the emails. Users…

more

should upgrade to Mail 2.2.1 for Nextcloud 25, Mail 1.14.5 for Nextcloud 22-24, Mail 1.12.9 for Nextcloud 21, or Mail 1.11.8 for Nextcloud 20 to receive a patch. No known workarounds are available.

CWE(s)
CWE-639

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
attack.mitre.org →
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.007 Proc Filesystem Credential Access
Adversaries may gather credentials from the proc filesystem or `/proc`.
attack.mitre.org →
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
attack.mitre.org →
T1011 Exfiltration Over Other Network Medium Exfiltration
Adversaries may attempt to exfiltrate data over a different network medium than the command and control channel.
attack.mitre.org →
T1016.002 Wi-Fi Discovery Discovery
Adversaries may search for information about Wi-Fi networks, such as network names and passwords, on compromised systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-66514Same product: Nextcloud Mail
CVE-2023-22471Same vendor: Nextcloud
CVE-2026-45281Same vendor: Nextcloud
CVE-2025-66546Same vendor: Nextcloud
CVE-2025-64011Same vendor: Nextcloud
CVE-2024-52507Same vendor: Nextcloud
CVE-2023-48307Same product: Nextcloud Mail
CVE-2023-23943Same product: Nextcloud Mail
CVE-2024-52511Same vendor: Nextcloud
CVE-2025-66513Same vendor: Nextcloud

Affected Assets

nextcloud
mail
≤ 1.11.8 · 1.12.0 — 1.12.9 · 1.13.0 — 1.14.5

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-24 Access Control Decisions
addresses: CWE-639

Per-request decision making makes it harder to bypass authorization using user-controlled keys without proper validation in the decision process.

AC-3 Access Enforcement
addresses: CWE-639

Consistent enforcement of approved authorizations makes bypassing via user-controlled keys ineffective.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 partial match
blocks

Enforcing authorization policy and least privilege directly blocks user-controlled key tampering that bypasses access checks.

PR.IR-01 partial match
blocks

Logical access controls prevent unauthorized data access that results from missing authorization checks on object references.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
blocks

A.5.15 directly requires defining and implementing access control rules (including authorization, need-to-know, role-based restrictions, formal requests, and consistency with classification) that stop one user from reaching another's data via a tampered key; the bounded remainder is dynamic or application-specific authorization logic (cross-referenced to 8.26) that may still allow bypass if those downstream rules are flawed.

A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
blocks

Managing access rights includes ensuring users can only access their own records and not bypass authorization by altering identifiers.

A.8.10 Information deletion partial match
removes

References