CVE-2025-20740 — TOCTOU Race Condition in Mediatek MT7902, MT7920, MT7921, MT7922, MT7925, MT7927
In wlan STA driver, there is a possible out of bounds read due to a race condition. This could lead to local information disclosure with User execution privileges needed. User interaction is not needed for exploitation. Patch ID: WCNCR00435337; Issue ID: MSV-4036.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.1% (30-day exploitation probability)+0
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
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.
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.
- Identify exposed assets running the affected vendor/product/version combinations (Mediatek MT7902, MT7920, MT7921, MT7922, MT7925, MT7927, Mediatek Software Development Kit).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (logic error), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Mediatek | MT7902, MT7920, MT7921, MT7922, MT7925, MT7927 | version NB SDK release 3.7 and before | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Mediatek | Software Development Kit | ≤ 3.7 | Vulnerable | NIST National Vulnerability Database |
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.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 4.7 | CVSS 3.1 | Medium | 1.0 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 4.7 | CVSS 3.1 | Medium | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.10%
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.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · mediatek, inc./mt7902, mt7920, mt7921, mt7922, mt7925, mt7927
- SSVC assessment updated
- Record published
- CVSS changed · 4.7
- Source status changed · → Analyzed
- Record created in this database
- 2025
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-20430 Out-of-bounds Write in Mediatek Software Development Kit Mar 2, 2026
- Medium CVE-2026-20419 Improper Check for Unusual or Exceptional Conditions in Mediatek Nbiot Sdk Feb 2, 2026
- High CVE-2026-20408 Out-of-bounds Write in Mediatek Software Development Kit Feb 2, 2026
- Medium CVE-2025-20748 Out-of-bounds Write in Mediatek Software Development Kit Nov 4, 2025
- High CVE-2025-20742 Out-of-bounds Write in Mediatek Software Development Kit Nov 4, 2025
- Medium CVE-2025-20741 Out-of-bounds Write in Mediatek Software Development Kit Nov 4, 2025
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-2025-20740 is "TOCTOU Race Condition in Mediatek MT7902, MT7920, MT7921, MT7922, MT7925, MT7927", rated Medium. It affects MT7902, MT7920, MT7921, MT7922, MT7925, MT7927 (Mediatek); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.7 describes technical severity. EPSS 0.10% 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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