# CVE-2026-18414: Out-of-bounds write in the ADI MAX32 ADC driver due to incorrect adc_sequence buffer size validation > A user-mode thread can trigger an out-of-bounds write in the MAX32 ADC driver, potentially leading to kernel code execution or privilege escalation. - **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** No - **Published:** 28 Sep 2026 - **Updated:** 30 Sep 2026 - **Also known as:** GHSA-ghm4-78mm-8v2c ## What is CVE-2026-18414? CVE-2026-18414 is a high-severity memory corruption vulnerability in Zephyrproject Zephyr, published on 28 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description The ADC API requires each driver to reject a sampling sequence whose destination buffer is too small: the buffer_size field of struct adc_sequence in include/zephyr/drivers/adc.h documents that "the driver must ensure that samples are not written beyond the limit and it must return an error if the buffer turns out to be not large enough". The ADI MAX32 driver did not honour that contract. start_read() in drivers/adc/adc_max32.c compared buffer_size, a byte count, against a sample count ((1 + extra_samplings) channels), ignoring sizeof(uint16_t), so it accepted a buffer half the required size. The samples are then stored through the uint16_t data->buffer by Wrap_MXC_ADC_GetData(), which writes two bytes per sample and advances the pointer by one uint16_t: in adc_max32_start_channel() for synchronous reads, and in adc_max32_isr() for asynchronous ones. A sequence selecting two channels with a two-byte buffer, for example, passes the check and has its second sample written past the end of the buffer. On a build with CONFIG_USERSPACE, adc_read() and adc_read_async() are system calls. The handler in drivers/adc/adc_handlers.c copies the sequence in from user memory, verifies only that [buffer, buffer + buffer_size) is writable by the calling thread, and rejects a user-supplied options->callback; it deliberately leaves the size arithmetic to the driver. A user-mode thread that has been granted access to a MAX32 ADC device object therefore fully controls channels, buffer, buffer_size and options->extra_samplings, and can make the driver write twice as many bytes as its buffer holds. Because the check scales with extra_samplings, the overrun equals the length of the buffer itself, up to channels * 65536 bytes past its end, since the sample pointer is only rewound on a repeat sampling, never on the extra samplings of a sequence. The resulting stores are performed by the driver in kernel mode (in the system call itself, the ADC context timer, or the ADC interrupt handler for asynchronous reads), where the MPU does not restrict the thread's memory domain, so the write walks linearly out of the user partition and into adjacent memory such as other partitions, kernel data or thread stacks. The impact is kernel-memory corruption of attacker-chosen length at an attacker-chosen offset, a plausible privilege-escalation and denial-of-service primitive from an unprivileged user-mode thread. Builds without CONFIG_USERSPACE are affected only as a caller-side robustness defect, since the application itself supplies the buffer. The fix replaces that check in start_read() with a call to the new shared helper adc_sequence_validate_buffer() in drivers/adc/adc_common.c, passing sizeof(uint16_t) as the sample size. The helper computes active_channels sizeof(uint16_t) (1 + extra_samplings) and returns -ENOMEM before any sampling is started. Weakness: CWE-787 (Out-of-bounds Write) ## Which versions are affected by CVE-2026-18414? It affects 1 product. Products: Zephyrproject Zephyr. ## How do I fix CVE-2026-18414? No fix has been published for CVE-2026-18414 yet. Limit exposure of the affected software until one is available. ## Is CVE-2026-18414 being exploited? There is no known exploitation of CVE-2026-18414 in the wild and no public exploit code. ## Other vulnerabilities in Zephyrproject Zephyr - [CVE-2026-5067](https://insights.sbomify.com/CVE-2026-5067/): Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key (critical 9.8) - [CVE-2022-3806](https://insights.sbomify.com/CVE-2022-3806/): Bluetooth HCI Error Handling Double Free (critical 9.8) - [CVE-2017-14199](https://insights.sbomify.com/CVE-2017-14199/): Memory corruption in getaddrinfo (critical 9.8) - [CVE-2018-1000800](https://insights.sbomify.com/CVE-2018-1000800/): Null dereference in n/a (critical 9.8) - [CVE-2021-3329](https://insights.sbomify.com/CVE-2021-3329/): DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer (critical 9.6) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-18414 and fix it if it is affected. What it is: CVE-2026-18414 is a high-severity memory corruption vulnerability in Zephyrproject Zephyr, published on 28 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-18414 in the wild and no public exploit code. Affected product: Zephyrproject Zephyr. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-18414/ (Markdown: https://insights.sbomify.com/CVE-2026-18414/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18414 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18414 - OSV: https://osv.dev/vulnerability/CVE-2026-18414 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-18414/ Summaries are generated and may contain mistakes; the official description above is the record.