Description
The Dhara flash translation layer disk driver (drivers/disk/ftl_dhara.c) implemented the dhara_nand_ callbacks so that, on a flash error, the error code was written unconditionally through the caller-supplied dhara_error_t err pointer (e.g. *err = DHARA_E_ECC in dhara_nand_read, and similar in dhara_nand_erase/prog/copy).

The upstream Dhara library calls these callbacks with err == NULL along its journal-resume binary search: find_last_checkblock() invokes find_checkblock(j, mid, &found, NULL), which forwards the NULL pointer into dhara_nand_read(). This path runs during disk_ftl_access_init() -> dhara_map_resume() whenever the FTL disk is mounted/initialised.

If a flash read error (uncorrectable ECC, bad block, controller error) occurs on one of the probed checkpoint pages, the driver dereferences and writes to NULL, faulting the kernel (denial of service). The trigger is conditioned on the NAND medium content/health, which can be influenced by media wear, induced faults, or a corrupted/crafted on-flash image.

The fix routes all error assignments through the library's NULL-safe dhara_set_error() helper. Affects Zephyr v4.4.0, where the driver was introduced.
Published: 2026-07-07
Score: 4.7 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The Dhara flash translation layer in Zephyr RTOS contains a NULL Pointer Dereference (CWE‑476) that occurs during the journal resume process when a flash read error happens. The driver writes an error code through a caller‑supplied pointer, but the Dhara library may pass a NULL pointer for checkpoint pages. When a checkpoint page fails to read, the driver dereferences and writes to this NULL pointer, causing the kernel to crash and resulting in a denial of service. This flaw is purely a memory error that can be triggered by hardware faults, media wear, or a deliberately corrupted on‑flash image.

Affected Systems

Zephyr Project’s Zephyr RTOS version 4.4.0 includes the vulnerable Dhara driver. The flaw was fixed in upstream commit a8371b0d4719efe37a66e2abb618ad9b81792212; firmware builds that incorporate this commit or later downstream releases are no longer affected.

Risk and Exploitability

The CVSS score of 4.7 indicates a moderate severity, while the EPSS score is less than 1 % and the vulnerability is not listed in the CISA KEV catalog, implying a low likelihood of public exploitation. Exploitation requires a flash read error during disk initialization—e.g., due to media wear, induced hardware faults, or a crafted flash image—so the attack surface is limited to boot or mount time. Based on the description, it is inferred that the attack vector is constrained to this narrow execution path, rendering real‑world exploitation probabilities low.

Generated by OpenCVE AI on August 4, 2026 at 07:47 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade Zephyr RTOS to a release that incorporates the Dhara driver fix, such as the upstream commit a8371b0d4719efe37a66e2abb618ad9b81792212 or any downstream firmware version that applies this change
  • If an OTA update or source upgrade is not feasible, apply the patch from the referenced commit to the source tree, rebuild, and flash the updated firmware
  • If neither option is immediately possible, isolate the affected device, disable the FTL disk feature during boot, or monitor NAND health and replace the flash when errors are detected

Generated by OpenCVE AI on August 4, 2026 at 07:47 UTC.

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History

Tue, 14 Jul 2026 19:00:00 +0000

Type Values Removed Values Added
Description The Dhara flash translation layer disk driver (drivers/disk/ftl_dhara.c) implemented the dhara_nand_ callbacks so that, on a flash error, the error code was written unconditionally through the caller-supplied dhara_error_t err pointer (e.g. *err = DHARA_E_ECC in dhara_nand_read, and similar in dhara_nand_erase/prog/copy). The upstream Dhara library calls these callbacks with err == NULL along its journal-resume binary search: find_last_checkblock() invokes find_checkblock(j, mid, &found, NULL), which forwards the NULL pointer into dhara_nand_read(). This path runs during disk_ftl_access_init() -> dhara_map_resume() whenever the FTL disk is mounted/initialised. If a flash read error (uncorrectable ECC, bad block, controller error) occurs on one of the probed checkpoint pages, the driver dereferences and writes to NULL, faulting the kernel (denial of service). The trigger is conditioned on the NAND medium content/health, which can be influenced by media wear, induced faults, or a corrupted/crafted on-flash image. The fix routes all error assignments through the library's NULL-safe dhara_set_error() helper. Affects Zephyr v4.4.0, where the driver was introduced. The Dhara flash translation layer disk driver (drivers/disk/ftl_dhara.c) implemented the dhara_nand_ callbacks so that, on a flash error, the error code was written unconditionally through the caller-supplied dhara_error_t err pointer (e.g. *err = DHARA_E_ECC in dhara_nand_read, and similar in dhara_nand_erase/prog/copy). The upstream Dhara library calls these callbacks with err == NULL along its journal-resume binary search: find_last_checkblock() invokes find_checkblock(j, mid, &found, NULL), which forwards the NULL pointer into dhara_nand_read(). This path runs during disk_ftl_access_init() -> dhara_map_resume() whenever the FTL disk is mounted/initialised. If a flash read error (uncorrectable ECC, bad block, controller error) occurs on one of the probed checkpoint pages, the driver dereferences and writes to NULL, faulting the kernel (denial of service). The trigger is conditioned on the NAND medium content/health, which can be influenced by media wear, induced faults, or a corrupted/crafted on-flash image. The fix routes all error assignments through the library's NULL-safe dhara_set_error() helper. Affects Zephyr v4.4.0, where the driver was introduced.

Tue, 07 Jul 2026 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Zephyrproject
Zephyrproject zephyr
Vendors & Products Zephyrproject
Zephyrproject zephyr

Tue, 07 Jul 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 07 Jul 2026 13:15:00 +0000

Type Values Removed Values Added
Description The Dhara flash translation layer disk driver (drivers/disk/ftl_dhara.c) implemented the dhara_nand_ callbacks so that, on a flash error, the error code was written unconditionally through the caller-supplied dhara_error_t err pointer (e.g. *err = DHARA_E_ECC in dhara_nand_read, and similar in dhara_nand_erase/prog/copy). The upstream Dhara library calls these callbacks with err == NULL along its journal-resume binary search: find_last_checkblock() invokes find_checkblock(j, mid, &found, NULL), which forwards the NULL pointer into dhara_nand_read(). This path runs during disk_ftl_access_init() -> dhara_map_resume() whenever the FTL disk is mounted/initialised. If a flash read error (uncorrectable ECC, bad block, controller error) occurs on one of the probed checkpoint pages, the driver dereferences and writes to NULL, faulting the kernel (denial of service). The trigger is conditioned on the NAND medium content/health, which can be influenced by media wear, induced faults, or a corrupted/crafted on-flash image. The fix routes all error assignments through the library's NULL-safe dhara_set_error() helper. Affects Zephyr v4.4.0, where the driver was introduced.
Title NULL pointer dereference in Zephyr Dhara FTL disk driver on flash read error during journal resume
Weaknesses CWE-476
References
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

Zephyrproject Zephyr
cve-icon MITRE

Status: PUBLISHED

Assigner: zephyr

Published:

Updated: 2026-07-14T18:38:42.162Z

Reserved: 2026-06-02T15:24:36.650Z

Link: CVE-2026-10659

cve-icon Vulnrichment

Updated: 2026-07-07T13:24:23.052Z

cve-icon NVD

Status : Modified

Published: 2026-07-07T13:16:29.043

Modified: 2026-07-14T19:16:49.500

Link: CVE-2026-10659

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-04T08:00:03Z

Weaknesses