CVE-2026-21127

Executive Summary

CVE-2026-21127 is a local information-disclosure vulnerability in the Samsung Account Android application caused by improper export of application components (CWE-926). Exploitation is restricted to a local attack vector: any code executing on the same device — including a malicious app installed by the user or side-loaded — can invoke the improperly exported component to access sensitive data held by Samsung Account. The flaw affects Samsung Account builds prior to version 15.7.01.1, potentially spanning a very large install base of Samsung Galaxy devices and any Android device with the Samsung Account package installed.

Technical Analysis

The vulnerability class here is an improper export of an Android application component. In Android, application components (activities, services, content providers, broadcast receivers) declare an android:exported attribute in the app manifest. When a component that handles or exposes sensitive data is marked exported — either explicitly or implicitly through an intent filter — without an accompanying permission guard, any other application on the same device can invoke it via an IPC mechanism such as an Intent, a bound service call, or a ContentProvider URI. This breaks the application sandbox boundary that normally isolates app data.

The NVD description states that the defect lies in Samsung Account prior to 15.7.01.1 and that it "allows local attackers to access sensitive data." The relevant attack surface is therefore the inter-process communication (IPC) interface exported by the Samsung Account app to other processes on the device. Because the vector is local (AV:L), the attacker profile is any principal capable of running code on the device: a malicious or repackaged application, a side-loaded APK, a compromised or untrusted app with the privilege to send intents, or an actor with ADB access to a developer-enabled device. No user interaction (UI:N) is required for the component invocation itself once such code is present.

Notably, the CVE record does not disclose which specific component is over-exported, what data fields it returns, or which Android permission (if any) is missing. No public proof-of-concept, exploit code, or Nuclei template is available, and no CNA title or vendor advisory was published alongside the record. The CWE assignment (CWE-926, Improper Export of Android Application Components) is consistent with the description and is the authoritative basis for this analysis. Any claim about specific class names, manifest attributes, intent actions, content authorities, or returned fields would be speculative and is therefore deliberately omitted here.

Two structural characteristics sharpen the risk. First, the lack of publicly documented fix details and the absence of OSV package metadata (OSV Packages: N/A) mean defenders cannot rely on automated dependency scanners to flag affected devices; version detection must be performed directly on the device package. Second, because Samsung Account is a system-adjacent application on many Samsung devices, its sensitive data set — account identifiers, session/token material, profile attributes, and device-linked account metadata — is inherently high-value for downstream account takeover, phishing, and correlation attacks. Without trace-level data, the confidential data category (C:H) is a prudent assumption in the vector above, but the true data class cannot be established from the record.

Exploitation Scenarios

No public PoC is available; the following chain is inferred strictly from the vulnerability class (CWE-926) and the local nature of the issue.

1. Reconnaissance / target identification: The attacker already possesses execution capability on the target device, typically through a malicious or repackaged app that the victim installs, or through ADB access on a developer-enabled device. The attacker enumerates installed packages and identifies the presence of the Samsung Account application, then inspects its manifest for exported components (activities, services, content providers) that are not protected by a signature-level or dangerous permission.

2. Triggering the flaw class: With the over-exported component identified, the attacker sends the component an IPC request — an explicit Intent, a bound-service call, or a ContentProvider query — from a separate application context. Because the component is exported without an adequate permission check, the caller is not rejected at the IPC boundary and the component processes the request under the Samsung Account app's own process identity and privileges.

3. Payload / execution method (class level): The "payload" is not code execution but a crafted IPC message. The attacker supplies the parameters the exposed component expects (for example, query arguments or intent extras), which causes the component to return or disclose data the calling app should never be able to reach. No fabricated endpoint or field names are asserted here because the record does not disclose them.

4. Post-exploitation impact: Sensitive data retrieved through the exposed component is exfiltrated by the malicious app over its own network channel or stored locally for later retrieval. Given that the data belongs to the Samsung Account domain, an attacker could use it for account correlation, targeted phishing, session or identity abuse, or as reconnaissance material for follow-on attacks. Because the disclosure is local, the attacker must already reside on the device — this vulnerability is an escalation/access enabler, not a remote entry point.

Impact Assessment

The vulnerability yields unauthorized local access to sensitive Samsung Account data. Under the CVSS v3.1 vector AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N, the impact is confined to confidentiality (High) with no integrity or availability effect and no scope change. The low attack complexity and lack of required privileges or user interaction mean that any malicious app on the device can reliably exercise the flaw. The blast radius is defined by the population of Samsung Account installations below 15.7.01.1, which is potentially very large across Samsung mobile and tablet devices. Business impact includes account-takeover enablement, loss of user trust, regulatory exposure from improper handling of personal data, and potential enterprise exposure on BYOD or managed devices where Samsung Account is present. The CVSS base score is not provided by the source record and is deliberately reported as N/A rather than estimated. EPSS has not been scored by FIRST.org.

Detection Guidance

Sigma Rule

title: Suspicious Invocation of Exported Samsung Account Component
id: 8f2c1b64-3a5e-4d0e-9a7b-2c1d4e6f7a90
status: experimental
description: Detects a background or third-party application invoking an exported Samsung Account IPC component, indicative of CVE-2026-21127 exploitation.
logsource:
  product: android
  service: app_activity
detection:
  selection_target:
    target_package|contains: 'com.samsung.android.samsungaccount'
  selection_anomaly:
    exported_component: true
    caller_uid_shared: false
  filter_legit:
    caller_package|startswith: 'com.samsung.android'
  condition: selection_target and selection_anomaly and not filter_legit
fields:
  - caller_package
  - caller_uid
  - target_package
  - component_name
  - timestamp
falsepositives:
  - Samsung system apps and trusted OEM integrations
level: medium
tags:
  - attack.collection
  - attack.t1409
  - cve.2026.21127

YARA Rule

rule Android_SamsungAccount_ExportedComponent_CVE_2026_21127
{
    meta:
        author = "SOC Threat Intelligence"
        description = "Heuristic detection of Samsung Account manifests exporting components without permission guards (CVE-2026-21127 class)"
        cve = "CVE-2026-21127"
        date = "2026-01-01"
    strings:
        $pkg = "com.samsung.android.samsungaccount" ascii wide nocase
        $exp = "android:exported=\"true\"" ascii wide nocase
        $manifest = "AndroidManifest.xml" ascii wide nocase
        $intentfilter = "intent-filter" ascii wide nocase
        $perm = "android:permission" ascii wide nocase
    condition:
        $pkg and $manifest and any of ($exp, $intentfilter) and not $perm
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-21127 Samsung Account Exported Component Data Exfiltration"; flow:established,to_server; http.user_agent; content:"SamsungAccountExfil"; nocase; http.header; content:"X-Caller-Package"; nocase; http.header; content:"com.samsung.android.samsungaccount"; nocase; threshold: type limit, track by_src, count 1, seconds 60; classtype:attempted-user; sid:202621127; rev:1;)

Elastic Detection

process where event.category == "process" and process.name != null and
  process.args like~ ("*com.samsung.android.samsungaccount*", "*exported*", "*content query*")
  and not process.parent.name like~ ("com.samsung.android*")
  and process.executable like~ ("/data/app/*", "/data/local/tmp/*")

Splunk SPL Query

index=android_logs sourcetype=android:activity_notification OR sourcetype=android:appops
| search (component_target="*samsungaccount*" OR target_package="*samsungaccount*") AND (exported=true OR caller_shared_uid=false)
| eval risk=case(match(caller_package,"^com\.samsung\."), "low", true(), "high")
| where risk="high"
| stats count min(_time) as first_seen max(_time) as last_seen by caller_package, target_package, component_name, src
| where count >= 2
| table first_seen, last_seen, caller_package, target_package, component_name, src, count

Wazuh OSSEC Rule

<group name="android,cve-2026-21127,">
  <rule id="20261127" level="8">
    <decoded_as>json</decoded_as>
    <field name="target_package">com.samsung.android.samsungaccount</field>
    <field name="exported_component">true</field>
    <field name="caller_package" negate="yes">com.samsung.android</field>
    <description>CVE-2026-21127: Unexpected third-party invocation of exported Samsung Account component</description>
    <mitre>
      <id>T1409</id>
    </mitre>
    <group>cve_2026_21127,android_security,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). No vendor advisory, OSV entry, or tracked fix reference is available for this CVE; the only version guidance is that of the NVD description (affected: prior to 15.7.01.1).

1. Immediate mitigations:

   • Restrict installation of apps from unknown sources and enforce a strict MDM allowlist on managed Android devices; this vulnerability requires local code execution, so blocking side-loaded/malicious apps removes the primary attack precondition.
   • Disable developer options and ADB debugging on production devices, removing ADB as a local attack path.
   • Remove or restrict access to Samsung Account on non-essential or high-sensitivity endpoints until a fixed version is confirmed.
   • Where an MDM/EMM solution permits, use app-level policies and permission controls to constrain inter-app IPC from untrusted applications.
   • Monitor devices for anomalous or unexpected Samsung Account application versions; treat any build below 15.7.01.1 as affected.

2. Patch/upgrade steps:

   • Check the installed Samsung Account version on each device and compare against 15.7.01.1. No verified patch artifact is tracked in this dataset; upgrade through the official channel (Google Play / Galaxy Store / Samsung firmware update) if and when Samsung publishes 15.7.01.1 or later.
   • Validate the version string directly on-device; do not rely on package scanner coverage, since OSV packages are not mapped for this CVE.
   • Re-audit after upgrade; retain an inventory of all devices that ran a version below 15.7.01.1 for retrospective monitoring.

3. Long-term hardening:

   • Establish device-side telemetry and application-manifest auditing to detect over-exported components before exploitation.
   • Require signature-level permission guards for any inter-app data exchange in Android application development and review.
   • Adopt a vulnerability-management process that treats missing-vendor-advisory cases (like this one) as unpatched until independently validated.
   • Maintain BYOD policy controls that limit the privileges and data reach of user-installed applications.

References

• NVD: CVE-2026-21127 — https://nvd.nist.gov/vuln/detail/CVE-2026-21127
• CWE-926: Improper Export of Android Application Components — https://cwe.mitre.org/data/definitions/926.html
• Android Developers: App security best practices (exported components and permissions) — https://developer.android.com/privacy-and-security/security-best-practices
• Android Developers: Intent and ContentProvider security — https://developer.android.com/guide/components/intents-filters
• CISA KEV catalog (listed: NO) — https://www.cisa.gov/known-exploited-vulnerabilities-catalog

No threat-actor campaign, exploitation-in-the-wild evidence, public PoC, or Nuclei template has been observed or reported for CVE-2026-21127 as of this writing.