CVE-2026-21048: libimagecodec Buffer Overflow Vulnerability

CVE-2026-21048 Overview

CVE-2026-21048 is an out-of-bounds write vulnerability in libimagecodec.media.quram.so, the Samsung image codec library responsible for parsing Digital Negative (DNG) image files. The flaw affects Samsung mobile devices prior to the SMR Jul-2026 Release 1 security maintenance release. Remote attackers can trigger memory corruption by delivering a crafted DNG file, writing beyond allocated buffer boundaries in the parser. Successful exploitation compromises integrity of the target process and may enable further attacker-controlled behavior.

Critical Impact
Remote attackers can write out-of-bounds memory in the DNG parser without authentication or user interaction, corrupting process memory on affected Samsung devices.

Affected Products

Samsung mobile devices running firmware prior to SMR Jul-2026 Release 1
libimagecodec.media.quram.so image codec library
Applications and system components that invoke the Quram DNG parser

Discovery Timeline

2026-07-10 - CVE-2026-21048 published to NVD
2026-07-10 - Last updated in NVD database
July 2026 - Samsung releases SMR Jul-2026 Release 1 with the fix

Technical Details for CVE-2026-21048

Vulnerability Analysis

The vulnerability resides in the DNG image parsing logic of libimagecodec.media.quram.so, a native library from Quram used by Samsung devices to decode image formats. DNG is Adobe's open raw image format based on the TIFF specification. Parsing DNG files requires interpreting nested Image File Directory (IFD) structures, tag entries, and variable-length pixel data.

When the parser processes a malformed DNG file, it writes data past the bounds of an allocated buffer. This out-of-bounds write [CWE-787] corrupts adjacent memory regions and can influence control-flow or data-flow within the media parsing process. The resulting integrity impact is rated high, while confidentiality is unaffected and availability impact is low.

Root Cause

The root cause is improper validation of size, offset, or count fields extracted from attacker-controlled DNG metadata before those values drive memory write operations. Length checks on tag values, strip offsets, or tile dimensions are either missing or performed against incorrect bounds, allowing the parser to write outside the destination buffer.

Attack Vector

The attack vector is network-reachable and requires no authentication. An attacker delivers a malicious DNG file through messaging applications, email attachments, web downloads, or any application that decodes images through the vulnerable Quram library. The passive attack requirement in the CVSS vector indicates the target must process the file, but no active user interaction beyond normal use is required in scenarios where images auto-render.

The vulnerability manifests during DNG header and tag parsing. Refer to the Samsung Security Update Notice for vendor technical details.

Detection Methods for CVE-2026-21048

Indicators of Compromise

Unexpected crashes or SIGSEGV signals in processes that load libimagecodec.media.quram.so
Tombstone files in /data/tombstones/ referencing the Quram library with fault addresses inside DNG parsing routines
Delivery of .dng files through messaging, MMS, or email to Samsung devices from untrusted senders

Detection Strategies

Monitor mobile device management (MDM) telemetry for Samsung endpoints running firmware below SMR Jul-2026 Release 1
Inspect network and email gateways for DNG attachments and correlate with recipients on unpatched devices
Review application crash reports from Samsung Members or vendor diagnostics for repeated faults in the image codec

Monitoring Recommendations

Track Samsung SMR patch level compliance across the mobile fleet through MDM or UEM reporting
Alert on inbound DNG files at mail and messaging gateways, especially from external senders
Retain mobile crash and tombstone logs to support post-incident forensic analysis

How to Mitigate CVE-2026-21048

Immediate Actions Required

Install the Samsung SMR Jul-2026 Release 1 security maintenance release on all affected devices
Enforce minimum patch level policies through MDM to block non-compliant devices from sensitive resources
Advise users to avoid opening DNG files from untrusted or unexpected sources until patched

Patch Information

Samsung addressed CVE-2026-21048 in the SMR Jul-2026 Release 1 firmware update. The fix corrects bounds checking in the DNG parsing routines of libimagecodec.media.quram.so. Details and per-model rollout status are published in the Samsung Security Update Notice.

Workarounds

Block DNG (.dng) attachments at email and messaging gateways where operational impact is acceptable
Disable automatic image preview and rendering in messaging applications on unpatched devices
Restrict installation of third-party applications that programmatically process raw camera images until firmware is updated

bash

# Verify Samsung security patch level on a connected device via ADB
adb shell getprop ro.build.version.security_patch

# Expected: 2026-07-01 or later to indicate SMR Jul-2026 Release 1 is installed