Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessInstall unprivileged malicious app on device
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DeliverySend crafted request to Video HAL
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ExploitOverflow stack buffer (missing bounds check)
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ExecutionExecute code in privileged HAL context
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ImpactEscalate to system/kernel privileges
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Stack buffer bounds checking
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Requires an attacker to already have local code execution on the device - typically an unprivileged app installed on an affected MediaTek-chipset Android device - that can reach the Video HAL interface and supply crafted input triggering the missing bounds check. Per the CVSS vector (AV:L/PR:N/UI:N), no additional privileges and no user interaction are needed once such local access exists, and default configurations appear affected. The primary limiting factor is the local attack vector: remote exploitation over a network is not indicated, so the flaw is an escalation primitive that presupposes prior on-device access, and it is scoped to the listed MediaTek chipsets (MT6xxx/MT8xxx/MT2718 families) running the unpatched Video HAL. |
| Impact | This is a genuine high-priority local privilege escalation, not merely an inflated CVSS number. The vendor-supplied CVSS:3.1 vector (AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, base 8.4) is internally consistent with the description: a missing bounds check in the Video HAL (CWE-121, stack-based buffer overflow) reachable locally with no privileges and no user interaction, yielding full confidentiality, integrity, and availability impact - effectively kernel/system-level code execution from an unprivileged context. The key mitigating signal is the attack vector: AV:L means exploitation requires local code execution first (e.g., a malicious or compromised app already on the device), so this is a chaining/escalation primitive rather than a remote entry point. No EPSS score, CISA KEV listing, or public POC is present in the provided data, so there is no evidence of active or widespread exploitation; absence of these signals is not proof of safety but does lower the immediate urgency relative to remotely-exploitable KEV-listed flaws. The decisive risk factor here is prevalence - MediaTek chipsets are in an enormous number of Android devices - so despite the local-only vector, the sheer deployment footprint and the clean no-UI/no-privilege escalation make this a priority patch for the October 2026 MediaTek security bulletin cycle. |
| Exploit ScenarioDerived | A user installs a seemingly benign app that, running with no special permissions, sends crafted input to the Video HAL interface and overflows a stack buffer due to the missing bounds check. The overflow is used to execute code in the privileged media/HAL context, letting the app escalate from an unprivileged sandbox to full system/kernel-level control without any user interaction. No public exploit code is identified in the provided data, so real-world exploitation would currently require an attacker to independently develop the exploit. |
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Alert meAnalysisAIv1 – Oct 05, 2026
Local privilege escalation in MediaTek's Video HAL lets an unprivileged app already running on an affected device corrupt a fixed-size stack buffer via crafted input to the video hardware abstraction layer, yielding code execution in the HAL context with high impact to confidentiality, integrity and availability (CVSS 8.4, AV:L/PR:N/UI:N). The flaw stems from a missing bounds check (CWE-121, stack-based buffer overflow) and affects roughly four dozen MediaTek chipsets spanning the MT6xxx, MT8xxx and MT2718 families used in Android phones, tablets, Chromebooks and automotive platforms. No user interaction and no additional execution privileges are required once local code execution exists, but the attack vector is local only - remote exploitation is not indicated and no public exploit code has been identified at time of analysis. MediaTek has assigned patch ID ALPS11375674 (issue MSV-9571), delivered to OEMs through its October 2026 product security bulletin.
RemediationAI
Patch status is patch available per vendor advisory: MediaTek has issued the Video HAL fix under patch ID ALPS11375674 (issue MSV-9571), but because the flaw lives in chipset firmware/BSP, the fix must be delivered by the device OEM - apply the latest OEM firmware or monthly Android security update for the specific model, using the MediaTek October 2026 Product Security Bulletin (https://www.mediatek.com/product-security-bulletin/October-2026) as the cross-reference when checking whether a given build includes the fix. Full remediation is limited for devices that have reached end of support and will never receive OEM firmware, so prioritize those for replacement or, in managed fleets, for network/app-level restriction. Compensating controls should target the precondition for exploitation, which is a locally installed app capable of reaching the Video HAL interface: enforce a managed allowlist that restricts installation to vetted enterprise or Play-distributed apps and disable unknown-source/sideloading (trade-off: blocks legitimate internal or line-of-business APKs and requires curated catalogues), keep Google Play Protect and on-device malware scanning enabled (trade-off: scanning overhead and occasional false positives), and disable USB debugging, developer options and OEM unlocking on production devices to remove an easy route to a local foothold (trade-off: breaks legitimate debugging, ADB automation and CI/QA workflows). For high-assurance deployments, revoke unnecessary camera/video/media permissions from untrusted apps and restrict media-capture intents (trade-off: degrades functionality of apps that legitimately record or process video), and keep the bootloader locked with verified boot enforced so that a post-exploitation payload cannot persist across reboots. There is no user-side fix that repairs the HAL itself; vendors/OEMs should consume the MediaTek BSP patch rather than attempting to hand-patch the stack-buffer validation logic. No public exploit code has been identified at time of analysis, so prioritization should be driven by the local-PE nature of the flaw and the very large affected SoC footprint rather than by observed exploitation.
Affected VersionsENISA
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Technical ContextAI · show details
A hardware abstraction layer (HAL) is the vendor-supplied translation layer that sits between Android's public framework APIs and MediaTek's proprietary drivers and firmware. The Video HAL handles capture, encode/decode and buffer management for camera/video pipelines and typically runs in a privileged native process with direct access to video kernel drivers and DMA-capable memory, which is why memory corruption there is an escalation primitive rather than a mere app crash. The root cause is CWE-121 (stack-based buffer overflow): attacker-controlled parameters in a Video HAL request - commonly a length, count, stride or format field - are used without validating them against the destination buffer size, so an oversized or malformed input writes past the end of a stack-allocated buffer and can overwrite saved registers and the return address. Successful exploitation allows the attacker to hijack control flow inside the HAL process, which runs with privileges an ordinary third-party app does not hold and can reach vendor driver interfaces, enabling privilege escalation and, potentially, persistent device compromise. The assessed vector CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H indicates low attack complexity, no privileges required and no user interaction; the only meaningful barrier is the requirement for a local foothold (an installed app that can reach the Video HAL interface), and default configurations are considered affected. Related weakness classes include out-of-bounds write (CWE-787) and general buffer overflow; vendor tags classify the issue as Privilege Escalation / Buffer Overflow / Stack Overflow.
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Severity by source
AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AV:L because exploitation needs prior on-device code execution; PR:N/UI:N per description (no privileges or interaction); C/I/A:H as HAL overflow yields full system-level compromise.
Primary rating from Vendor (mediatek).
CVSS VectorVendor: mediatek
Lifecycle Timeline
3DescriptionCVE.org
In Video HAL, there is a possible escalation of privilege due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS11375674; Issue ID: MSV-9571.
Articles & Coverage 1
Executive ViewAI
MediaTek chipsets used in Android phones, tablets, Chromebooks, and automotive platforms contain a high-severity local privilege escalation vulnerability (CVE-2026-20521) that allows an unauthenticated local attacker to execute code in the Video HAL context, compromising confidentiality, integrity, and availability. Affecting roughly four dozen MediaTek chipsets across the MT6xxx, MT8xxx, and MT2718 families, this flaw could impact a broad range of organizational and customer devices if a malicious app is installed. Leadership should prioritize device inventory and OEM patch tracking because no vendor-released patch identified at time of analysis and no public exploit identified at time of analysis, but the potential for widespread device compromise warrants immediate attention.
No vendor-released patch identified at time of analysis; interim mitigations include restricting installation of untrusted applications, monitoring for anomalous Video HAL activity, and applying OEM updates as soon as they are released. MediaTek patch ID ALPS11375674 (issue MSV-9571) is available to OEMs for incorporation.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.
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GHSA-qpf3-2wfg-8hrm
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB