CVE-2026-21017: Samsung SecTelephonyProvider Privilege Escalation (Medium Severity, Local Attack)

Technical summary

CVE-2026-21017 stems from inadequate privilege validation in SecTelephonyProvider prior to the June 2026 SMR 1 release. The vulnerability allows a process running with limited privileges to circumvent file access restrictions and read data that should be protected by the Android security model. The CVSS 3.1 score of 5.5 (Medium, AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N) reflects the local attack vector, low complexity, requirement for low privileges, and high confidentiality impact with no integrity or availability impact. The telephony provider component's role in handling sensitive communication metadata makes this particularly relevant for devices handling personal or enterprise calls.

Business impact

For organizations deploying Samsung Android devices—particularly in enterprise or BYOD environments—this vulnerability creates a data-leakage risk. An employee's device could expose call logs, contact information, or other telephony metadata if compromised by a malicious application or local attacker. The impact is bounded to confidentiality (no system instability or data corruption), but confidentiality breaches involving communications data can trigger compliance obligations under GDPR, HIPAA, or internal data-protection policies. The Medium severity rating reflects this: concerning enough to require patching, but not critical enough to warrant emergency response protocols.

Affected systems

The vulnerability affects Samsung Android devices running SecTelephonyProvider versions prior to the June 2026 SMR 1 release. The source data lists 40 entries for 'samsung android' without granular device model or OS version detail; this likely indicates a broad range of Samsung devices (Galaxy phones, tablets, and other Android devices) released over several years. Organizations should verify which specific device models and OS versions in their environment require patching by cross-referencing Samsung's official SMR documentation.

Exploitability

Exploitability is relatively low in the wild. The attack requires local access (the attacker or malicious app must already run on the device), low user privileges, and no user interaction. There is no network attack surface. This means the risk is primarily from sideloaded applications, rooted devices, or physical compromise—not remote exploitation. As of the data provided, this vulnerability is not listed on CISA's KEV (Known Exploited Vulnerabilities) catalog, suggesting active exploitation has not been confirmed in the public record, though the simplicity of the vulnerability (straightforward privilege-handling flaw) means exploitation code could be developed quickly if not already done privately.

Remediation

Apply Samsung's June 2026 SMR 1 release (or any later security patch) to affected devices. This is the authoritative fix; Samsung has bundled the SecTelephonyProvider correction into their monthly maintenance release. Organizations should verify patch applicability by device model and region, as Samsung releases patches incrementally. For devices that cannot be updated (end-of-life models), restrict installation of untrusted applications and enforce mobile device management (MDM) policies to limit what processes can run with user privileges.

Patch guidance

1. Identify all Samsung Android devices in your environment and their current OS/SMR version. 2. Check Samsung's security updates page or your MDM console for SMR Jun-2026 Release 1 availability for each device model and carrier. 3. Schedule and deploy the patch during a maintenance window, testing on a sample device first. 4. Prioritize devices handling sensitive communications (healthcare, legal, executive devices). 5. Document patch status for compliance audits. Samsung typically delivers patches monthly; ensure your update mechanisms are enabled and not deferred indefinitely.

Detection guidance

Monitor for signs of unauthorized file access to telephony-related system directories (typically under /data/telephony or similar protected paths) using SELinux audit logs (available on Android 5.0+). Mobile threat detection solutions may flag processes attempting unusual access patterns to the SecTelephonyProvider service. Review MDM logs for unpatched device inventory and prioritize those still running pre-June-2026 SMR 1 firmware. Behavioral signals (unusual data exfiltration, access logs showing unexpected telephony queries) should trigger investigation. However, detection is challenging for a local privilege issue; prevention (patching) and access control (MDM policies) are more effective than detection.

Why prioritize this

This vulnerability merits medium priority in patch cycles. The local-only attack vector and lack of known active exploitation reduce urgency compared to remote RCE flaws, but the confidentiality impact (potential exposure of call history and contact data) and broad device coverage justify inclusion in the next monthly security update. Prioritize devices in regulated industries (healthcare, finance, law enforcement) or those handling executive communications. For general enterprise deployment, batch this with other June 2026 SMR patches rather than treating it as an isolated emergency.

Risk score, explained

The CVSS 3.1 score of 5.5 (Medium) accurately reflects a flaw that is concerning but not critical. The local attack vector (AV:L) and low privilege requirement (PR:L) prevent a high score, but the high confidentiality impact (C:H) and the telephony component's sensitivity push it above 'Low.' There is no impact to integrity or availability, limiting the upper bound. For risk prioritization, consider raising the effective risk if your organization has devices in high-compliance environments or handles regulated communications; the business context may warrant treating it as a higher priority than the base score alone suggests.

Frequently asked questions