CVE-2021-41256Public exploit

File read and write via reflected Intent

Published Nov 30, 2021 · Updated Aug 4, 2024

Improper Intent handling in Nextcloud News for Android before 0.9.9.63 allows local users to read or write external-storage files. The exported SettingsActivity.onStart method returns the caller-supplied Intent through setResult without clearing its data URI or permission-grant flags. A malicious application installed on the same device must launch the activity for a result; the reflected grant then exposes files through the app's non-exported FileProvider.

CVSS severity5.8
Medium
EPSS probability1.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper Intent handling in Nextcloud News for Android before 0.9.9.63 allows local users to read or write external-storage files. The exported SettingsActivity.onStart method returns the caller-supplied Intent through setResult without clearing its data URI or permission-grant flags. A malicious application installed on the same device must launch the activity for a result; the reflected grant then exposes files through the app's non-exported FileProvider.

The record

CVE
CVE-2021-41256
Published
Nov 30, 2021
Updated
Aug 4, 2024
Vendor
Nextcloud GmbH
Product
Nextcloud News for Android
Classifications
CWE-829, T1409
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Nov 30, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=< 0.9.9.63

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Nextcloud GmbH · Nextcloud News for Androidversion=< 0.9.9.63

Published CVSS scores

5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:N
5.8GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-829Inclusion of Functionality from Untrusted Control Sphere
T1409Stored Application Data

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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