Samsung Notes CVE-2025-21057

Exploitation requires a separately-installed malicious or colluding Android application on the same Samsung device that registers an intent filter matching the implicit intent Samsung Notes uses to transmit shared-note data; the attacker gains access only to notes that are shared through that intent-based flow. Limiting factors are significant: the attack vector is local (AV:L) with no remote reach, it depends on the victim first installing an untrusted app, it only applies to Samsung Notes versions prior to 4.4.30.63, and impact is confined to disclosure of shared-note contents (confidentiality only, no modification or denial of service). It does not work against default single-device usage absent a hostile co-resident app.

This is a genuinely low-priority issue despite being a real vulnerability. All signals align toward minimal real-world risk: the CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N) scores only 3.3 (Low), reflecting local-only attack vector, required privileges (a malicious app must already be installed), and limited confidentiality-only impact with no integrity or availability effect. EPSS is 0.11% (1st percentile), indicating essentially no observed exploitation activity. The vulnerability is NOT in CISA KEV (no confirmed active exploitation), and no public exploit code was identified in the provided data. The SSVC-style read is: exploitation=none observed, technical impact=partial (information disclosure of shared notes only), and not automatable (requires a local malicious app staged on the device). The use of an implicit Android intent for sensitive communication is a legitimate design weakness, but the attacker must already have a foothold on the device, so this is a defense-in-depth hardening fix rather than an urgent threat. No conflicting signals are present; all sources consistently point to low severity.

A user installs a seemingly benign malicious Android app on a Samsung device running Samsung Notes below 4.4.30.63. Because Samsung Notes broadcasts shared-note data via an implicit intent, the malicious app registers an intent filter to silently receive that data and read the contents of shared notes without the user's knowledge. No public exploit code was identified at time of analysis, and the attack requires local presence on the device.