Security readout for executives and security teams
Plain-English summary
CVE-2019-5451 is a lock-screen bypass in the Nextcloud Android app before version 3.6.1. By rapidly opening and closing the app, someone with access to the device could view files despite the app’s lock protection. This is mainly a mobile device exposure issue, not a remote server compromise.
Executive priority
Treat as a targeted mobile confidentiality risk. Prioritize updates for executives, administrators, and users handling sensitive files on Android devices. This does not indicate compromise of the Nextcloud server itself.
Technical view
The issue is classified as CWE-288, Authentication Bypass Using an Alternate Path or Channel. Public sources describe bypassing Nextcloud Android app lock protection before 3.6.1 through repeated rapid app open/close actions, allowing access to files. No CVSS score or detailed affected-version range beyond “prior to 3.6.1” is provided in the source bundle.
Likely exposure
Organizations are most exposed where users store or sync sensitive files in the Nextcloud Android app and rely on the app lock feature. Exposure appears to require access to the Android device and vulnerable app version before 3.6.1.
Exploitation context
The CVE is not listed in CISA KEV, and the provided sources do not report active exploitation. The described attack is local and timing-based, requiring repeated app open and close actions in a short period.
Researcher notes
Public detail is limited. The source bundle identifies the affected component as com.nextcloud.client and describes the vulnerable behavior, but provides no CVSS vector and no evidence of active exploitation. Validate only in authorized test environments and avoid reproducing against user devices.
Mitigation direction
- Update the Nextcloud Android app to version 3.6.1 or later where available.
- Ask users to verify Android app versions on managed and unmanaged devices.
- Review vendor guidance and the HackerOne report for any additional recommendations.
- Use device-level screen locks and mobile device management controls where applicable.
Validation and detection
- Inventory Android devices using the Nextcloud app.
- Identify installations running versions prior to 3.6.1.
- Confirm whether app lock protection is enabled on affected devices.
- Document remediation status after upgrade or removal.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-288: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2019-5451 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://hackerone.com/reports/507172CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Authentication Bypass Using an Alternate Path or Channel
Authentication Bypass Using an Alternate Path or Channel represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.