CVE-2019-15615

Lock protection bypass via system time rollback

Published Feb 4, 2020 · Updated Aug 5, 2024

Improper authentication in Nextcloud Android app 3.9.0 allows attackers to bypass lock protection by setting the device clock to the past. The lock-check logic accepts a rolled-back system time, so the passcode gate is skipped. Physical access to the device is required, after which attackers can access and modify protected files through the client.

CVSS severity6.1
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Nextcloud Android app 3.9.0 allows attackers to bypass lock protection by setting the device clock to the past. The lock-check logic accepts a rolled-back system time, so the passcode gate is skipped. Physical access to the device is required, after which attackers can access and modify protected files through the client.

The record

CVE
CVE-2019-15615
Published
Feb 4, 2020
Updated
Aug 5, 2024
Vendor
Nextcloud GmbH
Product
Nextcloud Android app
Classifications
CWE-284, CWE-287
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.9.1

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Nextcloud GmbH · Nextcloud Android appversion=3.9.1

Published CVSS scores

3.6NVDAV:L/AC:L/Au:N/C:P/I:P/A:N
6.1NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
CWE-287Improper Authentication

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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