CVE-2025-21042

What it actually does

CVE-2025-21042 is an out-of-bounds write vulnerability in Samsung's Quram image codec library, libimagecodec.quram.so, present before Samsung Mobile Security Maintenance Release Apr-2025 Release 1. When a crafted image or image-bearing content is parsed, the codec can write outside the intended memory buffer, corrupt process memory and enabling arbitrary code execution. Because image parsing is often triggered automatically by messaging, gallery, browser, preview, or document-handling components, exploitation may require little or no user interaction depending on the delivery vector and application context. Successful exploitation can allow execution in the context of the vulnerable process and may be chained with sandbox escapes or privilege escalation to deploy spyware or other persistent mobile malware.

Why it matters to the business

This is a high-severity, actively exploited mobile device vulnerability that can lead to spyware installation, data theft, surveillance, and loss of device integrity. It is listed in CISA KEV with a remediation due date of 2025-12-01, and has been associated with the LANDFALL Android spyware campaign, increasing urgency for organizations with Samsung Android devices. Operational consequences include exposure of corporate communications, credentials, files, MFA prompts, location data, and managed app data from compromised devices. Even where ransomware use is not reported, the espionage and surveillance risk is significant, especially for executives, privileged users, journalists, legal staff, government personnel, and other high-value mobile users.

How an attack unfolds

An attacker delivers a specially crafted image or image-containing payload to a Samsung Android device through a channel that causes the Quram image codec to parse the content. The vulnerable libimagecodec.quram.so library mishandles the malformed image data and performs an out-of-bounds write, corrupting memory in the parsing process. With a reliable exploit, the attacker pivots from memory corruption to controlled code execution. In real-world exploitation associated with LANDFALL, this capability has reportedly been used as part of an Android spyware campaign, where code execution is used to stage additional payloads, collect sensitive data, and maintain surveillance. More advanced attacks may chain this flaw with additional Android or OEM-specific vulnerabilities to escape app sandboxing, gain elevated privileges, or persist across device activity.

How to fix it

Update affected Samsung mobile devices to Samsung Mobile Security Maintenance Release Apr-2025 Release 1 or later. Where centralized mobile device management is available, enforce minimum patch-level compliance and block access for devices below the April 2025 Samsung security maintenance release. Prioritize high-risk and high-value users first, including executives, administrators, legal, finance, government-facing, and users with access to sensitive communications or privileged systems. If immediate patching is not possible, reduce exposure by disabling automatic media download or preview in messaging and collaboration apps where supported, restricting installation of untrusted apps, enforcing mobile threat defense controls, and isolating unmanaged or noncompliant devices from corporate resources. Because exploitation has been observed in the wild, devices suspected of compromise should not only be patched; they should also be forensically reviewed and, where confidence cannot be established, factory reset and re-enrolled from a trusted baseline.

How to confirm the fix worked

Confirm that Samsung devices report a security patch level and vendor firmware level at or after SMR Apr-2025 Release 1. Validate compliance through MDM/UEM inventory, device settings, Android security patch level reporting, and Samsung firmware build information. Confirm that libimagecodec.quram.so is from a patched firmware image where binary inventory is available. Test policy enforcement by ensuring devices below the required patch level are flagged, quarantined, or denied access according to organizational policy. For exposure assessment, inventory Samsung Android devices, compare OS/security patch levels against the April 2025 Samsung maintenance release, and identify users with risky messaging or media-handling exposure. For suspected compromise, preserve mobile forensic data before factory reset, including logs, crash artifacts, app inventory, network telemetry, and mobile EDR alerts.

Typical attack path

1. Identify Samsung Android devices running firmware prior to SMR Apr-2025 Release 1.
2. Select a delivery channel likely to trigger automatic or user-assisted image parsing, such as messaging, chat, email, browser preview, social media, or file-sharing content.
3. Send a malformed image or image-bearing payload crafted to trigger the out-of-bounds write in libimagecodec.quram.so.
4. Exploit memory corruption to achieve code execution in the context of the vulnerable parsing process.
5. Optionally chain with sandbox escape, privilege escalation, or persistence techniques to expand control of the device.
6. Deploy spyware or a secondary payload to collect messages, files, credentials, microphone/camera data, location, or app data.
7. Exfiltrate collected information to attacker-controlled infrastructure and attempt to evade mobile security monitoring.

How to detect it

Look for evidence of exploitation in mobile security telemetry, Android crash logs, app crash reports, MDM/UEM device inventory, mobile EDR alerts, DNS/proxy logs from mobile devices, and forensic artifacts. Prioritize devices with Samsung firmware prior to SMR Apr-2025 Release 1 that show crashes in libimagecodec.quram.so, media parsing components, messaging apps, gallery apps, browser preview processes, or document/media handlers shortly after receiving image content. Review Android tombstones and native crash reports for backtraces referencing libimagecodec.quram.so, heap corruption, SIGSEGV, SIGABRT, or crash_dump activity. Correlate those crashes with suspicious post-crash behavior such as unknown app installation, sideloaded APKs, newly granted accessibility permissions, device admin activation, VPN/profile changes, unusual background services, microphone/camera access, abnormal battery or data usage, and outbound connections to rare or newly observed domains. Because LANDFALL is associated with spyware activity, also review for targeted delivery patterns, unusual messages from unknown senders, device compromise alerts, anomalous cloud account access after mobile activity, and exfiltration-like traffic. Absence of crash logs does not rule out exploitation, as mature exploits may suppress or clean artifacts.

• libimagecodec.quram.so
• /system/lib64/libimagecodec.quram.so
• /system/lib/libimagecodec.quram.so
• /data/tombstones/tombstone_
• crash_dump64
• crash_dump32
• signal 11 (SIGSEGV)
• signal 6 (SIGABRT)
• backtrace
• heap corruption
• quram
• LANDFALL
• Samsung Mobile Devices Out-of-Bounds Write Vulnerability
• LANDFALL Android spyware campaign

What your security team should do

• Treat this as urgent because it is in CISA KEV, has active in-the-wild exploitation, and is associated with the LANDFALL Android spyware campaign.
• Create an inventory of Samsung Android devices and identify all devices running firmware prior to SMR Apr-2025 Release 1.
• Enforce upgrade to Samsung SMR Apr-2025 Release 1 or later, prioritizing high-risk users and devices with access to sensitive data.
• Use MDM/UEM conditional access to quarantine or restrict devices that do not meet the minimum patch level before the 2025-12-01 KEV due date.
• Review mobile threat defense, EDR, proxy, DNS, and identity telemetry for signs of spyware behavior or suspicious device activity after media-message receipt.
• Investigate unexplained crashes involving libimagecodec.quram.so, especially if followed by unusual network connections, new app installs, accessibility-service abuse, or elevated battery/data usage.
• For devices suspected of exploitation, perform mobile forensic acquisition where feasible, rotate credentials and session tokens used from the device, and consider factory reset or device replacement.
• Educate high-risk users to avoid opening unexpected media files and to report suspicious messages, while emphasizing that patching is the primary control because some delivery paths may require minimal interaction.