CVE-2021-25489 — Samsung Mobile Devices Improper Input Validation Vulnerability

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

CISA required action CISA

Apply updates per vendor instructions or discontinue use of the product if updates are unavailable

US federal deadline: Jul 20, 2023 — passed 1183 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Samsung Android, Samsung Mobile Samsung Mobile Devices).
2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-134 · Use of Externally-Controlled Format String

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

EPSS over time FIRST

Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 0.53%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
• Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
• Hunt retroactively in logs from before Jun 29, 2023 (KEV listing): exploitation may have started earlier.

Timeline

What happened to this CVE, newest first.

• 2026
• Affected products added · samsung mobile/samsung mobile devices
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 13, 2026
• Affected products added · samsung/android
  Oct 13, 2026 · NIST National Vulnerability Database
• CVSS changed · 5.5
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Added to CISA KEV (detected)
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• Record created in this database
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• 2023
• Added to CISA KEV catalog
  Jun 28, 2023 · CISA
• 2021
• CVE published
  Oct 6, 2021 · Samsung Mobile

Source activity

Repeated readings are counted rather than listed.

• 2× References added · Oct 13, 2026 – Oct 13, 2026
• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

• security.samsungmobile.com/securityUpdate.smsb
  Vendor Advisory, x_refsource_MISC, NIST National Vulnerability Database
• www.cisa.gov/known-exploited-vulnerabilities-catalog
  US Government Resource, NIST National Vulnerability Database
• github.com/advisories/GHSA-hmpv-pvg5-4fpq
  GitHub Security Advisories
• nvd.nist.gov/vuln/detail/CVE-2021-25489
  GitHub Security Advisories

Elsewhere on this site

Related CVEs (same products)

• Medium CVE-2026-21126 Improper input validation in getting cover image in libsimba.heifdec.media.samsung.so prior to... 3d
• High CVE-2026-21125 Improper input validation in parsing sheifd in libsimba.heifdec.media.samsung.so prior to SMR Oct... 3d
• High CVE-2026-21124 Improper input validation in getting cover image in libsimba.heifdec.media.samsung.so prior to... 3d
• Medium CVE-2026-21123 Improper privilege management in Locksettings prior to SMR Oct-2026 Release 1 allows local... 3d
• High CVE-2026-21122 Out-of-bounds write in libsamsungtts.so prior to SMR Oct-2026 Release 1 allows local attackers to... 3d
• High CVE-2026-21120 Use after free in WSM service prior to SMR Oct-2026 Release 1 allows local attackers to... 3d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No fixed version, patch or mitigation documented.
• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2021-25489 is "Samsung Mobile Devices Improper Input Validation Vulnerability", rated Medium. It affects Android (Samsung); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 5.5 describes technical severity. EPSS 0.53% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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