Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploiting an ext4 parser in a bootloader needs attacker-controlled boot media, so AV:L not AV:N; no auth exists at boot stage (PR:N), and code execution pre-OS yields full C/I/A impact.
AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
Primary rating from Vendor (mitre).
CVSS VectorVendor: mitre
Lifecycle Timeline
5DescriptionCVE.org
An issue was discovered in Denx U-Boot before 2026.04. An integer overflow vulnerability exists in function ext4fs_get_bgdtable, the size calculation can lead to under allocation and this underallocated buffer will be used in memcpy() which could lead to arbitrary code execution, a denial of service, or other unspecified impacts.
AnalysisAI
Heap-based buffer overflow in Das U-Boot (the Denx universal embedded bootloader) before 2026.04 allows an attacker who controls an ext4 filesystem image to trigger an integer overflow in the ext4fs_get_bgdtable() block-group descriptor table size calculation, resulting in an undersized allocation that is later overrun by memcpy(). Successful exploitation can lead to arbitrary code execution in the highly privileged pre-OS boot context, denial of service, or memory corruption. No public exploit identified at time of analysis (a referenced GitHub gist may contain a proof-of-concept but is unverified), EPSS is low at 0.18% (7th percentile), and it is not listed in CISA KEV.
Technical ContextAI
U-Boot is the de-facto bootloader for embedded and IoT devices, responsible for initializing hardware and loading the OS kernel - often from an ext2/3/4 filesystem on eMMC, SD, USB, or network-boot media. The flaw is CWE-122 (heap-based buffer overflow) rooted in an integer overflow (CWE-190 class) during a size computation in ext4fs_get_bgdtable(), the routine that reads the ext4 block group descriptor table. Attacker-controlled filesystem metadata (e.g., a manipulated block-group count in the ext4 superblock) causes the descriptor-table size math to wrap, under-allocating the heap buffer; the subsequent memcpy() then writes past the allocation. Because U-Boot executes with full physical memory access and no OS-level memory protection, corruption here can yield complete control of the boot flow. The fix is upstream commit adccdb2, incorporated before the 2026.04 release.
RemediationAI
Upstream fix available (commit adccdb2); update to U-Boot 2026.04 or later, which contains the corrected ext4fs_get_bgdtable() size handling - rebuild and reflash the bootloader for all affected device images (note that flashing a bootloader carries bricking risk and typically requires a maintenance/recovery path). Because bootloaders are vendor-integrated, also track your SoC/board vendor's BSP release incorporating the fix. As compensating controls where reflashing is not immediately feasible: restrict physical access to boot media and disable booting from untrusted removable media (USB/SD) in the boot configuration, which prevents attacker-supplied ext4 images but may break legitimate field-update workflows; if the ext4 driver is not required, build U-Boot without CONFIG_FS_EXT4 to remove the vulnerable code path entirely, at the cost of losing ext4 boot support; and enforce verified/secure boot with signed images so a tampered filesystem is rejected before parsing where the platform supports it. Reference advisory: https://seclists.org/oss-sec/2026/q3/607.
Same weakness CWE-122 – Heap-based Buffer Overflow
View allVendor StatusVendor
SUSE
Severity: Important| Product | Status |
|---|---|
| SUSE Linux Enterprise Desktop 15 SP7 | Affected |
| SUSE Linux Enterprise Micro 5.3 | Affected |
| SUSE Linux Enterprise Micro 5.4 | Affected |
| SUSE Linux Enterprise Micro 5.5 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | Affected |
| SUSE Linux Enterprise Server 15 SP7 | Affected |
| SUSE Linux Enterprise Server 16.0 | Affected |
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Affected |
| SUSE Linux Micro 6.0 | Affected |
| SUSE Linux Micro 6.1 | Affected |
| SUSE Linux Micro 6.2 | Affected |
| SUSE Linux Micro Extras 6.0 | Affected |
| openSUSE Leap 16.0 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP5 | Affected |
| SUSE Linux Enterprise Server 12 SP5 | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Affected |
| SUSE CaaS Platform 4.0 | Affected |
| SUSE Enterprise Storage 6 | Affected |
| SUSE Enterprise Storage 6 | Affected |
| SUSE Linux Enterprise Desktop 15 SP1 | Affected |
| SUSE Linux Enterprise Desktop 15 SP1 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | Affected |
| SUSE Linux Enterprise Server 15 SP1 | Affected |
| SUSE Linux Enterprise Server 15 SP1 | Affected |
| SUSE Linux Enterprise Server 15 SP1-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | Affected |
| SUSE Manager Proxy 4.0 | Affected |
| SUSE Manager Proxy 4.0 | Affected |
| SUSE Manager Retail Branch Server 4.0 | Affected |
| SUSE Manager Retail Branch Server 4.0 | Affected |
| SUSE Manager Server 4.0 | Affected |
| SUSE Manager Server 4.0 | Affected |
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External POC / Exploit Code
Leaving vuln.today
EUVD-2025-210792
GHSA-jgm9-xpcw-hqh9