CVE-2023-28999
Nextcloud 3.0.5 – 4.8.0
Raw vector
CVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:LSummary
CVE-2023-28999 is a medium-severity Missing Cryptographic Step (CWE-325) vulnerability in Nextcloud Nextcloud. Its CVSS base score is 6.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Network Sniffing (T1040); ranked at the 49th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-32617
Vulnerability Data
Nextcloud is an open-source productivity platform. In Nextcloud Desktop client 3.0.0 until 3.8.0, Nextcloud Android app 3.13.0 until 3.25.0, and Nextcloud iOS app 3.0.5 until 4.8.0, a malicious server administrator can gain full access to an end-to-end encrypted folder. They…
more
can decrypt files, recover the folder structure and add new files. This issue is fixed in Nextcloud Desktop 3.8.0, Nextcloud Android 3.25.0, and Nextcloud iOS 4.8.0. No known workarounds are available.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
—
—
- 21 hardening rules · 9 OS baselines
—
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.
Privacy and security training stresses encryption of sensitive data, reducing missing encryption weaknesses.
Exchange agreements must document security requirements, which would include encryption to protect sensitive data in transit.
The map highlights data actions that involve sensitive data, enabling identification of missing encryption requirements.
Settings can require encryption of sensitive data, preventing missing encryption weaknesses.
Architectures must describe confidentiality protections, which includes mandating encryption for sensitive data in transit and at rest.
Privacy and security curricula stress encryption requirements, reducing missing encryption of sensitive data.
Requires encryption and similar controls for CUI processed or stored externally, preventing missing encryption of sensitive data.
Monitoring detects missing encryption of sensitive data in storage or transit configurations.
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.DS-01 directly mandates encryption for data-at-rest and therefore prevents CWE-311 mostly for storage, yet the weakness also spans transmission and other contexts that this single at-rest control leaves unaddressed.
Secure SDLC practices explicitly include correct cryptographic algorithm implementation and testing.
Proper encryption of data-in-transit requires all algorithm steps; omitting one directly weakens the control.
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.
Security testing can detect incomplete crypto implementations but does not itself enforce correct algorithm steps.
Explicit rules requiring encryption for sensitive information in transit eliminate the weakness of sending data without cryptographic protection.
Mandates correct use of cryptographic controls, directly preventing omission of required algorithm steps.
Secure SDLC processes reduce the likelihood of missing crypto steps but do not guarantee algorithm completeness.
Explicitly calling for protection of data in transit and at rest, plus secure encryption of communications, drives the implementation of encryption that prevents clear-text exposure of sensitive information.
Requires secure coding practices that would catch missing cryptographic steps during development.
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` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (3 rules)
- V-248524 OL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
- V-248525 All OL 8 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at-rest protection. prevents CWE-311
- V-248535 The OL 8 shadow password suite must be configured to use a sufficient number of hashing rounds. prevents CWE-325
Oracle Linux 9 (2 rules)
- V-271454 OL 9 must enable FIPS mode. prevents CWE-325
- V-271756 OL 9 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection. prevents CWE-311
RHEL 7 (1 rule)
- V-204497 The Red Hat Enterprise Linux operating system must implement NIST FIPS-validated cryptography for the following: to provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
RHEL 8 (2 rules)
- V-230223 RHEL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
- V-230224 All RHEL 8 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection. prevents CWE-311
RHEL 9 (1 rule)
- V-257879 RHEL 9 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection. prevents CWE-311
Ubuntu 22.04 (1 rule)
- V-260650 Ubuntu 22.04 LTS must implement NIST FIPS-validated cryptography to protect classified information and for the following: To provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
Ubuntu 24.04 (1 rule)
- V-270744 Ubuntu 24.04 LTS must implement NIST FIPS-validated cryptography to protect classified information and for the following: To provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
Windows Server 2016 (1 rule)
- V-224843 Systems requiring data at rest protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. prevents CWE-311
Windows Server 2019 (1 rule)
- V-205727 Windows Server 2019 systems requiring data at rest protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. prevents CWE-311