CVE-2026-20504 — In Modem, there is a possible system crash due to a missing bounds check. This could…
In Modem, there is a possible system crash due to a missing bounds check. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY00755024; Issue ID: MSV-7865.
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
- 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 MediaTek chipset, Mediatek Mt2735 Firmware, Mediatek Mt6833 Firmware…).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Mediatek | MediaTek chipset |
version MT6889version MT6833version MT6853version MT6855version MT6873version MT6875version MT6877version MT6880 and 11 moreversion MT6883version MT6885version MT2735version MT6890version MT6891version MT6893version MT8675version MT8771version MT8791version MT8791Tversion MT8797 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Mediatek | Mt2735 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6833 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6853 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6855 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6873 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6875 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6877 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6880 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6883 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6885 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6889 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6890 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6891 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt6893 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt8675 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt8771 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt8791 Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt8791t Firmware | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Mediatek | Mt8797 Firmware | versions not specified by the source | 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 |
|---|---|---|---|---|---|
| 5.3 | CVSS 3.1 | Medium | 1.6 | 3.6 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 5.3 | CVSS 3.1 | Medium | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Not enough vector or weakness data: use the affected application’s logs as a starting point.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · mediatek, inc./mediatek chipset
- SSVC assessment updated
- Record published
- CVSS changed · 5.3
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-20589 Out-of-bounds Write in Mediatek Mt2718 Firmware 10d
- Medium CVE-2026-20588 Out-of-bounds Write in Mediatek Mt2718 Firmware 10d
- Medium CVE-2026-20579 Out-of-bounds Write in Mediatek Mt2718 Firmware 10d
- Medium CVE-2026-20587 Type Confusion in Mediatek Mt2718 Firmware 10d
- Medium CVE-2026-20543 In Modem, there is a possible information disclosure due to a logic error. This could… 10d
- Medium CVE-2026-20540 In Modem, there is a possible out of bounds read due to a missing bounds check. This… 10d
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 FIRST EPSS score.
- 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-2026-20504 is "In Modem, there is a possible system crash due to a missing bounds check. This could…", rated Medium. It affects MediaTek chipset (Mediatek); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.3 describes technical severity. 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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