Integer overflow in U-Boot
CVE-2026-71973
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.
Vulnerability class: Integer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 5.2 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/u-boot/u-boot/commit/561ae28cb56a082cfa90c1c421c4955bc215470b (patch)
- github.com/u-boot/u-boot/blob/v2026.07/fs/squashfs/sqfs.c (technical-description)
- github.com/u-boot/u-boot (product)
- www.vulncheck.com/advisories/u-boot-before-2026.10-rc4-integer-overflow-in-squa… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-71973?
- CVE-2026-71973 is a medium-severity vulnerability in U-Boot, classified under Integer Overflow or Wraparound. CVSS score: 5.2/10. Published 2026-09-29.
- How severe is CVE-2026-71973?
- Medium severity. CVSS v3 base score is 5.2 out of 10.