CVE-2026-20503
Modem System Denial of Service Vulnerability
Description
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: MOLY01371002; Issue ID: MSV-9020.
INFO
Published Date :
Sept. 7, 2026, 2:17 a.m.
Last Modified :
Sept. 9, 2026, 2:55 a.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-20503
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Apply the vendor patch.
- Update the affected modem firmware.
- Ensure proper bounds checking is implemented.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-20503.
| URL | Resource |
|---|---|
| https://www.mediatek.com/product-security-bulletin/September-2026 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-20503 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-20503
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-20503 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-20503 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 09, 2026
Action Type Old Value New Value Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt2716_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt2716:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt2735_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt2735:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt2737_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt2737:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6813_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6813:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6833_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6833:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6835_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6835:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6853_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6853:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6855_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6855:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6858_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6858:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6873_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6873:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6875_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6875:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6877_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6877:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6878_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6878:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6879_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6879:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6880_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6880:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6881_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6881:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6883_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6883:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6885_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6885:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6886_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6886:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6889_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6889:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6890_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6890:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6891_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6891:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6893_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6893:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6895_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6895:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6896_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6896:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6897_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6897:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6899_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6899:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6980_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6980:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6982vb_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6982vb:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6983_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6983:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6985_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6985:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6986_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6986:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6988_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6988:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6989_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6989:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6990_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6990:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6991_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6991:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt6993_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt6993:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8668_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8668:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8673_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8673:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8675_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8675:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8676_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8676:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8678_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8678:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8755_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8755:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8771_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8771:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8775_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8775:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8791_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8791:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8791t_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8791t:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8792_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8792:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8793_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8793:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8795t_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8795t:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8796_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8796:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8797_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8797:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8798_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8798:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8863_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8863:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8873_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8873:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8883_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8883:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:mediatek:mt8893_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:mediatek:mt8893:-:*:*:*:*:*:*:* Added Reference Type MediaTek, Inc.: https://www.mediatek.com/product-security-bulletin/September-2026 Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 07, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Added SSVC {'id': 'CVE-2026-20503', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-07T10:37:13.041815Z'} -
New CVE Received by [email protected]
Sep. 07, 2026
Action Type Old Value New Value Added Description 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: MOLY01371002; Issue ID: MSV-9020. Added CWE CWE-617 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/20xxx/CVE-2026-20503.json">CVE-2026-20503</a> Added Reference https://www.mediatek.com/product-security-bulletin/September-2026