CVE-2026-0170 Overview
CVE-2026-0170 is an out-of-bounds write vulnerability in the Vp9DecodeFrameTag function of vp9hwd_headers.cc. The flaw stems from a missing bounds check during VP9 frame tag decoding. Successful exploitation leads to remote escalation of privilege without requiring additional execution privileges or user interaction. The vulnerability is tracked under CWE-787: Out-of-bounds Write and was published in the Android Security Bulletin September 2026.
Critical Impact
A remote attacker can trigger memory corruption in the VP9 hardware decoder path to achieve privilege escalation without user interaction.
Affected Products
- Android platform components implementing the VP9 hardware decoder (vp9hwd_headers.cc)
- Google Pixel devices referenced in the September 2026 Pixel security bulletin
- Downstream Android distributions incorporating the vulnerable VP9 decoding module
Discovery Timeline
- 2026-09-15 - CVE-2026-0170 published to the National Vulnerability Database
- 2026-09-16 - Last updated in NVD database
Technical Details for CVE-2026-0170
Vulnerability Analysis
The vulnerability resides in the Vp9DecodeFrameTag function within vp9hwd_headers.cc, a source file responsible for parsing VP9 video frame headers on the hardware decoder path. The routine processes frame tag metadata but omits a bounds check before writing decoded fields into a fixed-size buffer. An attacker who supplies a crafted VP9 stream can drive the decoder into writing beyond the intended memory region.
Because the flaw sits in media parsing code that typically runs with elevated privileges in the Android media stack, successful exploitation yields privilege escalation within the media service context. The attack does not require user interaction, so any pathway that feeds untrusted VP9 content into the vulnerable decoder is sufficient to trigger the condition.
Root Cause
The root cause is a missing bounds check [CWE-787] during frame tag deserialization. The decoder trusts length or index values derived from attacker-controlled header fields and writes into an adjacent memory region without validating that the destination offset remains within the allocated buffer. This corrupts adjacent heap or stack structures depending on the allocation layout.
Attack Vector
Exploitation requires delivering a malicious VP9-encoded video to a vulnerable Android device. Delivery channels include messaging applications, browser-based media playback, and any application that decodes remote VP9 content through the platform decoder. Once the crafted frame is parsed, the out-of-bounds write can be shaped to overwrite function pointers or object metadata, enabling code execution with the privileges of the media component. See the Android Security Bulletin September 2026 for platform-specific details.
No verified public proof-of-concept code is available.
Refer to the Android Security Bulletin for technical details.
Detection Methods for CVE-2026-0170
Indicators of Compromise
- Unexpected crashes or restarts of the Android media server or hardware decoder process when handling VP9 content
- Malformed VP9 streams delivered through messaging, browsing, or media-sharing applications
- Anomalous privilege escalation events originating from media-processing service contexts
Detection Strategies
- Monitor Android system logs (logcat, tombstones) for SIGSEGV or SIGABRT crashes referencing Vp9DecodeFrameTag or vp9hwd_headers
- Inspect inbound video content for VP9 frames with anomalous frame tag lengths or field values that deviate from the VP9 bitstream specification
- Correlate media decoder crashes with subsequent unauthorized process launches or capability changes
Monitoring Recommendations
- Ingest mobile device telemetry into a centralized analytics pipeline to identify decoder-crash clusters across the fleet
- Track Android security patch level (ro.build.version.security_patch) across managed devices to confirm September 2026 patch adoption
- Alert on unusual media parsing latency or repeated decoder resets that may indicate exploitation attempts
How to Mitigate CVE-2026-0170
Immediate Actions Required
- Apply the September 2026 Android security patch level or later on all managed Android and Pixel devices
- Restrict auto-download of media attachments in messaging applications until patches are deployed
- Prioritize patching for devices that process untrusted video content, including devices used for messaging and social media
Patch Information
Google addressed the vulnerability in the September 2026 Android Security Bulletin. Device vendors ship the fix through the platform security patch level dated 2026-09-01 or later. Consult the Android Security Bulletin September 2026 for the authoritative patch reference and the corresponding AOSP commit.
Workarounds
- Disable auto-play and auto-download of video content in messaging and social applications
- Block untrusted VP9 media at network egress or MDM policy where feasible
- Enforce mobile threat defense policies that quarantine devices missing the September 2026 patch level
# Verify Android security patch level on a managed device
adb shell getprop ro.build.version.security_patch
# Expected output: 2026-09-01 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
