Uncontrolled format strings
Untrusted input becomes formatting instructions that can read or change program memory.
CWE-134 · NVD record: nvd@nist.gov
Practice labs · Free account. Advanced: C, assembly and binary exploitation experience are useful.
Exploited. On CISA's list since 2023-06-29.
Samsung Mobile Devices Improper Input Validation Vulnerability
CVE-2021-25489 · Samsung Mobile Devices · Published 2021-10-06
How bad would it be?
5.5 out of 10
CVSS rates it medium.
How likely is it to be used?
0.5%
Estimated chance of exploitation in the next 30 days, higher than 44% of all scored flaws (EPSS, 2026-10-29).
Is it already being used?
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 1198 days ago (2023-07-20).
What CISA says to do
Apply updates per vendor instructions or discontinue use of the product if updates are unavailable
Samsung mobile devices contain an improper input validation vulnerability within the modem interface driver that results in a format string bug leading to kernel panic.
What the flaw is
Assuming radio permission is gained, missing input validation in modem interface driver prior to SMR Oct-2021 Release 1 results in format string bug leading to kernel panic.
From the NVD.
Fixes and advisories
Learn this
Explore this week’s weaknesses and all learning topics
Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.
CWE-20 · CISA KEV; NVD record: mobile.security@samsung.com. We have not selected a close learning match for this label.
CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.
On SentryFeed
No story in the last 14 days has mentioned it.
Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.