Security Resilience

CVE-2023-26041

Nextcloud Talk 15.0.0 – 15.0.3

Public PoC
Published
27 February 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 2.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N
EPSS Score 0.0080 56th percentile
Risk Priority 27 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-2023-26041 is a low-severity Exposure of Private Personal Information to an Unauthorized Actor (CWE-359) vulnerability in Nextcloud Nextcloud Talk. Its CVSS base score is 2.6 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Protocol or Service Impersonation (T1001.003); ranked in the top 44% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

Nextcloud Talk is a fully on-premises audio/video and chat communication service. When cron jobs were misconfigured and therefore messages are not expired, the API would still return them while they were then hidden by the frontend code. It is recommended…

more

that the Nextcloud Talk is upgraded to 15.0.3. There are no workaround available.

CWE(s)
CWE-359CWE-668

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1016 System Network Configuration Discovery Discovery
Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.
attack.mitre.org →
T1021.002 SMB/Windows Admin Shares Lateral Movement
Adversaries may use [Valid Accounts](https://attack.
attack.mitre.org →
T1021.003 Distributed Component Object Model Lateral Movement
Adversaries may use [Valid Accounts](https://attack.
attack.mitre.org →
T1021.008 Direct Cloud VM Connections Lateral Movement
Adversaries may leverage [Valid Accounts](https://attack.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-66510Same vendor: Nextcloud
CVE-2023-2703Shared CWE-359, CWE-668
CVE-2023-7014Shared CWE-359, CWE-668
CVE-2023-29203Shared CWE-359, CWE-668
CVE-2023-35151Shared CWE-359, CWE-668
CVE-2023-28834Same vendor: Nextcloud
CVE-2023-48308Same vendor: Nextcloud
CVE-2026-45543Same vendor: Nextcloud
CVE-2023-25817Same vendor: Nextcloud
CVE-2024-22404Same vendor: Nextcloud

Affected Assets

nextcloud
nextcloud talk
15.0.0 — 15.0.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V10.3.5
  • V10.7.2

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-22 Publicly Accessible Content
addresses: CWE-359 CWE-668

Preventing nonpublic personal information from public posting reduces unauthorized exposure of private personal data.

AC-23 Data Mining Protection
addresses: CWE-359 CWE-668

The control detects and protects against mining of private personal information, reducing unauthorized exposure of PII.

CM-12 Information Location
addresses: CWE-359 CWE-668

Tracking locations of sensitive data and access users reduces risk of private personal information exposure.

SC-42 Sensor Capability and Data
addresses: CWE-359 CWE-668

Mandatory user notification of sensor activation makes surreptitious capture of private personal information (camera, microphone, location, etc.) substantially harder to perform without detection.

AC-15 Automated Marking
addresses: CWE-359

Automated marking identifies private personal information in outputs, tangibly reducing the ability to exploit weaknesses that result in its unauthorized exposure.

AC-16 Security and Privacy Attributes
addresses: CWE-359

Privacy-specific attributes and their controlled association directly reduce exposure of private personal information through missing or incorrect labeling.

AC-20 Use of External Systems
addresses: CWE-668

Controls whether organization resources are exposed to external system spheres by permitting or prohibiting their use.

AC-21 Information Sharing
addresses: CWE-668

The control ensures information is not released into a security sphere where the recipient lacks matching access authorizations.

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.

RC.CO-04 partial match
degrades

CWE-359 does not impair RC.CO-04's ability to issue approved public recovery updates, yet any resulting PII exposure can partially undermine the outcome's overall efficacy and trust.

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.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.5.34 Privacy and protection of PII partial match
blocks

A.5.34 only requires a policy, procedures, roles (e.g. privacy officer) and unspecified 'appropriate' measures; it does not itself stop unauthorized access to PII and depends on other controls (e.g. access enforcement) to do so, per the owner's explicit rule on dependency vs. effect.

A.8.10 Information deletion partial match
removes

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Ubuntu 22.04 (1 rule)
  • V-260531 Ubuntu 22.04 LTS must configure the SSH daemon to use FIPS 140-3-approved ciphers to prevent the unauthorized disclosure of information and/or detect changes to information during transmission. blocks CWE-359
Ubuntu 24.04 (1 rule)
  • V-270670 Ubuntu 24.04 LTS must configure the SSH client to use FIPS 140-3 approved ciphers to prevent the unauthorized disclosure of information and/or detect changes to information during transmission. blocks CWE-359

References