Signed offset bypasses bounds check in simulated EEPROM driver, allowing out-of-bounds kernel memory read and write from user mode
Summary
| CVE | CVE-2026-90833 |
|---|---|
| State | PUBLISHED |
| Assigner | zephyr |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-11-10 22:21:14 UTC |
| Updated | 2026-11-10 22:21:14 UTC |
| Description | The simulated EEPROM driver validated access ranges in eeprom_range_is_valid() (drivers/eeprom/eeprom_simulator.c) with a single test, (offset + len) <= config->size. Because offset is a signed off_t and len an unsigned size_t of the same rank, the addition is evaluated in unsigned arithmetic: a negative offset combined with a compensating len wraps the sum back into the accepted range. eeprom_sim_read() and eeprom_sim_write() then memcpy() through the EEPROM(addr) macro, which is plain pointer arithmetic on the driver's static mock_eeprom array, so the copy addresses memory located before that array. eeprom_read() and eeprom_write() are __syscall entry points, and their verification handlers in drivers/eeprom/eeprom_handlers.c check only the device object and the caller's own data buffer (K_SYSCALL_MEMORY_READ/K_SYSCALL_MEMORY_WRITE) — the offset argument is passed to the driver unvalidated. With CONFIG_USERSPACE=y, a CONFIG_EEPROM_SIMULATOR device instance, and the device object granted to a user thread (the usage the in-tree tests/drivers/eeprom/api suite exercises from ZTEST_USER threads), an unprivileged thread could supply a negative offset and have the kernel perform the copy on its behalf. The result is an out-of-bounds read of kernel .bss returned into the caller's buffer and, via the write path, an out-of-bounds write of caller-supplied bytes over kernel memory preceding mock_eeprom. Both the start address and the length of the affected span are attacker-selected, so the primitive is sufficient to corrupt adjacent kernel state and escape the user-mode sandbox. Exposure is limited to builds that instantiate the simulated EEPROM (status = "okay" by default on qemu_x86 and native_sim, otherwise added by a devicetree overlay) together with userspace isolation. The fix rejects negative offsets and performs the remaining bound check without overflow. |
Risk And Classification
Primary CVSS: v3.1 7.8 HIGH from [email protected]
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Problem Types: CWE-787 | CWE-787 bounds
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Zephyrproject | Zephyr | affected 2.2.0 4.3.2 semver | Not specified |
| CNA | Zephyrproject | Zephyr | affected 4.4.0 4.5.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-vf6j-hcx8-... | [email protected] | github.com | |
| github.com/zephyrproject-rtos/zephyr/commit/ce2ec9b3a34d71f52f5d1d7491b9... | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.