CVE-2026-21095 Overview
CVE-2026-21095 is a heap-based buffer overflow [CWE-122] in the Digital Negative (DNG) decoder of libimagecodec.quram.so, an image parsing library used on Samsung mobile devices. The flaw affects devices running builds prior to the Samsung Maintenance Release (SMR) Sep-2026 Release 1. Remote attackers can execute arbitrary code by delivering a crafted DNG image to a vulnerable device. Because the vulnerable code runs during image parsing, exploitation can occur through common delivery channels that automatically process images.
Critical Impact
Remote attackers can achieve arbitrary code execution on unpatched Samsung devices by delivering a malformed DNG image to the vulnerable decoder.
Affected Products
- Samsung mobile devices using libimagecodec.quram.so prior to SMR Sep-2026 Release 1
- Samsung Galaxy devices receiving the September 2026 Samsung Mobile Security Maintenance Release
- Applications and system components that invoke the Quramsoft DNG decoder for image parsing
Discovery Timeline
- 2026-09-09 - CVE-2026-21095 published to the National Vulnerability Database (NVD)
- September 2026 - Samsung addresses the issue in the SMR Sep-2026 Release 1 security maintenance release
- 2026-09-10 - Last updated in NVD database
Technical Details for CVE-2026-21095
Vulnerability Analysis
The vulnerability resides in the DNG decoder implemented in libimagecodec.quram.so, a Quramsoft image parsing library bundled with Samsung mobile firmware. DNG (Digital Negative) is a container format for raw camera data that includes complex tag structures, image strips, and embedded thumbnails.
During parsing of a crafted DNG file, the decoder writes past the bounds of a heap-allocated buffer. The out-of-bounds write corrupts adjacent heap metadata or object pointers, allowing an attacker to steer control flow. Successful exploitation grants execution in the context of the process that invoked the decoder, which typically holds access to user media, messaging content, and network resources.
Root Cause
The issue is classified as a heap-based buffer overflow [CWE-122]. The decoder does not correctly validate size or count fields extracted from attacker-controlled DNG metadata before using them to size or index into a destination heap buffer. When the computed length exceeds the allocation, the decoder writes attacker-supplied bytes beyond the allocated region.
Attack Vector
The attack vector is network-reachable. An attacker delivers a malicious DNG file to a target device through channels that automatically decode image content, including multimedia messaging, chat applications, email, or web pages. No privileges are required, and the decoder path can be reached without user interaction in some rendering scenarios, though certain delivery paths may require the user to open a message or preview an attachment.
Because libimagecodec.quram.so is loaded by multiple system and application processes, the same malformed input can be used against different attack surfaces. Public exploit code for CVE-2026-21095 is not currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.
No verified proof-of-concept code is available. Refer to the Samsung Mobile Security Update September 2026 advisory for vendor-provided technical details.
Detection Methods for CVE-2026-21095
Indicators of Compromise
- Unexpected crashes or tombstone files referencing libimagecodec.quram.so in system logs
- Anomalous child processes spawned by messaging, gallery, or media rendering applications immediately after image processing
- Inbound DNG or DNG-masquerading image files delivered through MMS, RCS, email, or chat platforms to unpatched devices
Detection Strategies
- Inspect image attachments in network and messaging telemetry for DNG magic bytes and malformed IFD (Image File Directory) tag structures
- Correlate application crash reports referencing the Quramsoft library with recent image ingestion events
- Track Samsung device firmware and security patch levels against the SMR Sep-2026 Release 1 baseline to identify exposed endpoints
Monitoring Recommendations
- Ingest mobile device management (MDM) patch-level telemetry into your security data lake to identify devices below SMR Sep-2026 Release 1
- Alert on repeated native crashes originating from image decoder libraries across a device fleet, which can indicate exploitation attempts
- Monitor egress from mobile devices for post-exploitation callbacks following inbound image delivery to prioritized users
How to Mitigate CVE-2026-21095
Immediate Actions Required
- Deploy the Samsung SMR Sep-2026 Release 1 maintenance release to all managed Samsung mobile devices through MDM policy
- Prioritize patching for high-risk users such as executives, journalists, and administrators whose devices commonly receive external media
- Advise users to avoid opening unsolicited image attachments and previews from unknown senders until patches are applied
Patch Information
Samsung addressed CVE-2026-21095 in the September 2026 Samsung Mobile Security Maintenance Release (SMR Sep-2026 Release 1). The updated libimagecodec.quram.so corrects the bounds handling in the DNG decoder. Patch availability varies by device model and carrier. Refer to the Samsung Mobile Security Update September 2026 bulletin for per-model rollout details.
Workarounds
- Disable auto-download of MMS and RCS attachments in messaging applications until the patch is installed
- Restrict messaging and email applications through MDM policy on high-risk devices pending firmware updates
- Block or quarantine DNG image attachments at the enterprise email gateway to reduce delivery vectors
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
