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Full vulnerability report · 2021
CVE-2021-0645High confidence

In shouldBlockFromTree of ExternalStorageProvider.java, there is a possible permissions bypass

n/a · Android

7.8HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-3264

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

In shouldBlockFromTree of ExternalStorageProvider.java, there is a possible permissions bypass. This could lead to local escalation of privilege, allowing an app to read private app directories in external storage, which should be restricted in Android 11, with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-157320644

What

In shouldBlockFromTree of ExternalStorageProvider.java, there is a possible permissions bypass. This could lead to local escalation of privilege, allowing an app to read private app directories in external storage, which should be restricted in Android 11, with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-157320644

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

In shouldBlockFromTree of ExternalStorageProvider.java, there is a possible permissions bypass. This could lead to local escalation of privilege, allowing an app to read private app directories in external storage, which should be restricted in Android 11, with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-157320644

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Incorrect Authorization → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-863 ↗

CWE-863: Incorrect Authorization. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
UnauthenticatedCWE-863
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

CERT-FR · French · CERTFR-2021-AVI-590Multiples vulnérabilités dans Google Android

.cve.org/CVERecord?id=CVE-2021-0581 Référence CVE CVE-2021-0582 https://www.cve.org/CVERecord?id=CVE-2021-0582 Référence CVE CVE-2021-0584 https://www.cve.org/CVERecord?id=CVE-2021-0584 Référence CVE CVE-2021-0591 https://www.cve.org/CVERecord?id=CVE-2021-0591 Référence CVE CVE-2021-0593 https://www.cve.org/CVERecord?id=CVE-2021-0593 Référence CVE CVE-2021-0639 https://www.cve.org/CVERecord?id=CVE-2021-0639 Référence CVE CVE-2021-0640 https://www.cve.org/CVERecord?id=CVE-2021-0640 Référence CVE CVE-2021-0641 https://www.cve.org/CVERecord?id=CVE-2021-0641 Référence CVE CVE-2021-0642 https://www.cve.org/CVERecord?id=CVE-2021-0642 Référence CVE CVE-2021-0645 https://www.cve.org/CVERecord?id=CVE-2021-0645 Référence CVE CVE-2021-0646 https://www.cve.org/CVERecord?id=CVE-2021-0646 Référence CVE CVE-2021-1904 https://www.cve.org/CVERecord?id=CVE-2021-1904 Référence CVE CVE-2021-1914 https://www.cve.org/CVERecord?id=CVE-2021-1914 Référence CVE CVE-2021-1916 https://www.cve.org/CVERecord?id=CVE-2021-1916 Référence CVE CVE-2021-1919 https://www.cve.org/CVERecord?id=CVE-2021-1919 Référence CVE CVE-2021-1920 https://www.cve.org/CVERecord?id=CVE-2021-1920 Référence CVE CVE-2021-1929 https://www.cve.org/CVERecord?id=CVE-2021-1929 Référence CVE CVE-2021-1930 https://www.cve.org/CVERecord?id=CVE-2021-1930 Ré

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Android-11
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 17 Aug 2021 · Last source change 3 Aug 2024, 15:47 UTC · CWE-863 · Incorrect Authorization

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-3264
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2021-3264↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-0645 · cve.blacktree.nl