CVE-2025-21042 Samsung Mobile Devices: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Dec 1, 2025
What to do
- Install Samsung's security update for Mobile Devices. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Install system updates the day they come out — most phone zero-days are fixed in a point release.
- Restart your phone every few days; some spyware does not survive a reboot.
- If you are a journalist, activist, lawyer, politician or executive, turn on Lockdown Mode (iPhone) or Advanced Protection (Android).
Who is affected
Could reach you. This one is aimed at devices or apps of the kind people own.
What's at risk: Messages, photos, location, microphone and camera. The most serious ones are "zero-click": no tap needed from the owner. They are usually used as spyware against a small number of chosen people.
The details
- Official name
- Samsung Mobile Devices Out-of-Bounds Write Vulnerability
- Product
- Samsung Mobile Devices
- CISA description
- Samsung mobile devices contain an out-of-bounds write vulnerability in libimagecodec.quram.so. This vulnerability could allow remote attackers to execute arbitrary code.
- Type of flaw
- Memory-safety flaw (CWE-787)
- Confirmed exploited
- Nov 10, 2025
- US federal patch deadline
- Dec 1, 2025
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Answering about CVE-2025-21042 ·
Questions about CVE-2025-21042
Is CVE-2025-21042 being exploited?
Yes. CISA added CVE-2025-21042 to its Known Exploited Vulnerabilities catalog on Nov 10, 2025, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2025-21042?
Install Samsung's security update for Mobile Devices. If no update exists, follow the vendor's workaround or stop using the product until one ships. Install system updates the day they come out — most phone zero-days are fixed in a point release.
Am I affected by CVE-2025-21042?
Only if you use Samsung Mobile Devices. This one is aimed at devices or apps of the kind people own.