Description
U-Boot before 2026.10-rc4 contains an integer overflow vulnerability in sqfs_read_directory_table() function when allocating the directory table buffer. Attackers can supply a crafted SquashFS image with an attacker-controlled superblock metablks_count value that causes heap buffer under-allocation and out-of-bounds writes, corrupting heap memory and crashing the bootloader.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| u-boot | u-boot | < 2026.10-rc4 | 2026.10-rc4 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | u-boot | No fix yet | — |
| Debian 13 | u-boot | No fix yet | — |
| Debian 12 | u-boot | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | u-boot | No fix yet | — |
| Ubuntu 26.04 LTS | u-boot | No fix yet | — |
| Ubuntu 24.04 LTS | u-boot +1 | No fix yet | — |
| Ubuntu 22.04 LTS | u-boot +1 | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | u-boot | No fix yet | — |
| Ubuntu Pro 18.04 LTS | u-boot | No fix yet | — |
| Ubuntu Pro 16.04 LTS | u-boot | No fix yet | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | qemu | No fix yet | — |
Advisories 1
- WID-SEC-2026-3660 DENX U-Boot: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 21, 2026
References
- https://github.com/u-boot/u-boot/commit/561ae28cb56a082cfa90c1c421c4955bc215470b patch
- https://github.com/u-boot/u-boot/blob/v2026.07/fs/squashfs/sqfs.c#L814 technical-description
- https://github.com/u-boot/u-boot product
- VulnCheck Advisory: U-Boot before 2026.10-rc4 Integer Overflow in SquashFS Directory Table Allocation third-party-advisory