CVE-2026-45527 Overview
CVE-2026-45527 is an integer overflow vulnerability [CWE-190] in the convertCleanApertureToRect function of HeifCleanAperture.cpp. The flaw affects Android's High Efficiency Image Format (HEIF) processing logic. An attacker can trigger a temporary denial of service (DoS) condition remotely without user interaction. The vulnerability is documented in the Android Security Bulletin for September 2026.
Critical Impact
Remote attackers can trigger a temporary denial of service through crafted HEIF image content without user interaction or elevated privileges.
Affected Products
- Android operating system components processing HEIF images
- HeifCleanAperture.cpp image parsing logic
- Refer to the Android Security Bulletin September 2026 for specific version details
Discovery Timeline
- 2026-09-08 - CVE-2026-45527 published to NVD
- 2026-09-10 - Last updated in NVD database
Technical Details for CVE-2026-45527
Vulnerability Analysis
The vulnerability resides in the convertCleanApertureToRect function of HeifCleanAperture.cpp. This function converts HEIF Clean Aperture (clap) box parameters into rectangular coordinate values used during image rendering. During arithmetic operations on the clean aperture width, height, and offset fields, an integer overflow occurs when the parsed values exceed the storage bounds of the target integer type.
When the overflow condition triggers, the resulting rectangle values become invalid. The image processing pipeline then encounters unexpected state, producing a temporary denial of service. The impacted process becomes unresponsive or crashes until it is restarted.
The issue does not enable code execution or information disclosure. The scope is limited to availability of the affected component.
Root Cause
The root cause is missing or insufficient bounds validation on arithmetic operations performed against attacker-controlled HEIF metadata. The Clean Aperture box in the HEIF container format stores fractional values as signed integer numerator and denominator pairs. Multiplication and subtraction on these values without range checks allows the result to wrap around, violating the function's implicit invariants.
Attack Vector
An attacker delivers a specially crafted HEIF image to the target device. Any workflow that decodes the image can invoke the vulnerable path, including messaging attachments, shared media, or content rendered by applications relying on the platform HEIF decoder. Exploitation requires network reachability but no user interaction and no elevated privileges beyond those already granted to the delivery channel.
No public proof-of-concept code has been released for CVE-2026-45527. For technical validation details, consult the Android Security Bulletin September 2026.
Detection Methods for CVE-2026-45527
Indicators of Compromise
- Repeated crashes or restarts of media processing services handling HEIF content
- tombstone or logcat entries referencing HeifCleanAperture or convertCleanApertureToRect
- Inbound HEIF files with anomalously large or negative Clean Aperture box parameters
Detection Strategies
- Inspect HEIF files traversing email, messaging, and file-sharing gateways for malformed clap box values
- Correlate application crash telemetry with recent HEIF media rendering events
- Monitor endpoint logs for repeated denial-of-service style crashes in image decoders
Monitoring Recommendations
- Enable crash reporting from Android media framework components to a centralized log store
- Track logcat output for stack traces referencing the HEIF decoder
- Alert on unusual volumes of HEIF attachments delivered to mobile endpoints in short time windows
How to Mitigate CVE-2026-45527
Immediate Actions Required
- Apply the September 2026 Android security patch level or later on all managed devices
- Restrict rendering of HEIF attachments from untrusted senders in messaging applications
- Validate that mobile device management (MDM) policies enforce current patch levels
Patch Information
Google addressed CVE-2026-45527 in the September 2026 Android Security Bulletin. Device manufacturers ship the corresponding patch under Android security patch level 2026-09-01 or later. Verify the patch status on managed devices using MDM reporting or the device Settings menu. See the Android Security Bulletin September 2026 for full remediation details.
Workarounds
- Disable automatic media preview in messaging and email clients until devices receive the patch
- Block HEIF attachments at the mail gateway for high-risk user groups
- Route mobile traffic through inspection points that can strip or sanitize HEIF payloads
# Verify Android security patch level on a connected 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.
