Vulnerability · Published Sep 29, 2026 · Assigned by VulnCheck
CVE-2026-71973U-Boot before 2026.10-rc4 Integer Overflow in SquashFS Directory Table Allocation
Medium 5.2
In plain English
A medium-severity integer overflow in u-boot from u-boot. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | u-boot | no fix listed | DEBIAN-CVE-2026-71973 |
| Debian:13 | u-boot | no fix listed | DEBIAN-CVE-2026-71973 |
| Debian:14 | u-boot | no fix listed | DEBIAN-CVE-2026-71973 |
| Ubuntu:22.04:LTS | u-boot | no fix listed | UBUNTU-CVE-2026-71973 |
| Ubuntu:24.04:LTS | u-boot | no fix listed | UBUNTU-CVE-2026-71973 |
| Ubuntu:26.04:LTS | u-boot | no fix listed | UBUNTU-CVE-2026-71973 |
| Ubuntu:26.10 | u-boot | no fix listed | UBUNTU-CVE-2026-71973 |
| Ubuntu:22.04:LTS | u-boot-nezha | no fix listed | UBUNTU-CVE-2026-71973 |
| Ubuntu:24.04:LTS | u-boot-nezha | no fix listed | UBUNTU-CVE-2026-71973 |
Affected products (as reported)
Weakness: CWE-190 · Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
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