CVE-2025-21042: Samsung Mobile Devices Out-of-Bounds Write Vulnerability

CVE-2025-21042 is an out-of-bounds write vulnerability affecting Samsung mobile devices in the library libimagecodec.quram.so. According to CISA, this flaw could allow remote attackers to execute arbitrary code. For IT and security teams managing fleets of Samsung phones or tablets, the issue matters because successful exploitation can give an attacker control over the device, potentially leading to data access, persistence, or further network movement if the device is connected to corporate resources.

Public detail is limited to the CISA summary and the CWE classification; exact attack vectors, affected firmware builds, and severity metrics must be confirmed against the vendor advisory before prioritizing response.

How it works

The vulnerability is classified as CWE-787, an out-of-bounds write. In this class of flaw, a program writes data past the end (or before the beginning) of an allocated buffer. On Samsung mobile devices the affected component is libimagecodec.quram.so, which handles image decoding. When malformed or specially crafted image data is processed, the library can write outside its intended memory region.

An attacker who can deliver such data to the vulnerable library—commonly through a remote channel that causes the device to parse an image—may corrupt adjacent memory structures. That corruption can be leveraged to alter control flow and achieve arbitrary code execution in the context of the process that loads the library. No specific exploit mechanics, payload formats, or privilege levels beyond the CISA description are provided in the available facts; defenders should treat any remote image-processing path as a potential entry point until the vendor advisory clarifies the exact conditions.

Am I affected? How to find it in your systems

The vulnerability is reported against Samsung mobile devices. Typical environments include employee-owned or company-issued Galaxy phones and tablets that process images via system or third-party applications relying on the Quram image codec library.

• Inventory all Samsung Android devices enrolled in MDM, EMM, or asset-management systems; record model, Android version, and security-patch level.
• On a sample of devices, locate libimagecodec.quram.so (commonly under system library paths) and note its presence; the mere existence of the library indicates the component is installed, but only the vendor advisory can map specific builds to the vulnerable state.
• Review application inventories for any software that decodes images using system codecs, including messaging, email, browser, and gallery apps.
• Examine device logs and MDM telemetry for unexpected process crashes, memory-corruption indicators, or anomalous image-processing activity originating from untrusted sources. Because public exploitation details are limited, treat any unexplained remote code execution on Samsung devices as potentially related until proven otherwise.

Confirm exact affected versions and configurations solely against Samsung’s security advisory; do not rely on generic Android patch levels alone.

How to remediate

The primary remediation is to apply the vendor-supplied update that addresses CVE-2025-21042. Follow Samsung’s official instructions for the security patch or firmware release that resolves the out-of-bounds write in libimagecodec.quram.so. CISA’s required action is to apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for any cloud-managed services, or discontinue use of the product if mitigations are unavailable.

• Push the update through MDM or instruct users to install the latest security patch via Settings > Software update.
• Verify successful installation by checking the security-patch date or build number against the advisory.
• After patching, re-inventory devices to confirm the vulnerable library version has been replaced.
• For residual risk, apply standard hardening for mobile image-processing components: restrict installation of untrusted apps, enforce app-permission least privilege, and keep the entire OS and apps current.

If you can't patch immediately

When immediate patching is not feasible, reduce exposure with compensating controls appropriate to the out-of-bounds write and remote-code-execution class.

• Segment Samsung devices onto restricted network segments or apply zero-trust policies that limit their ability to reach sensitive internal resources.
• Use mobile threat-defense or endpoint-detection tools to monitor for anomalous behavior in image-decoding processes and to quarantine suspicious files.
• If the environment allows, disable or restrict automatic image loading in messaging, email, and browser applications so that untrusted images are not decoded without user interaction.
• Apply virtual patching via network or host-based controls that block known malicious image patterns, understanding that signature coverage for this specific library may be incomplete until vendors release signatures.
• Increase logging and alerting around process crashes and memory-related events on Samsung devices; retain logs for forensic review.

These measures buy time but do not eliminate the underlying vulnerability; schedule patching as soon as operationally possible.

If your data may have been exposed

Actively exploited remote-code-execution vulnerabilities can lead to device compromise and subsequent data exposure. Although ransomware use is not documented for this CVE, any successful exploitation could allow an attacker to exfiltrate credentials, messages, or files stored on the device. Organizations should review device logs, network traffic, and authentication records for signs of compromise. Individuals whose devices may have been affected can run a free exposure scan of their email addresses against known breach data sets to determine whether personal information has already appeared in public or underground collections. Containment, credential rotation, and full device re-imaging remain the recommended recovery steps when compromise is confirmed.