CVE-2026-71973: Integer Overflow (CVSS 5.2)

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.

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CVSS v3.1 Score

5.2

MEDIUM

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS — Exploit Prediction

0.0019

Probability of exploitation

0.07%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-190 Integer Overflow

References

Other References

https://github.com/u-boot/u-boot https://github.com/u-boot/u-boot/blob/v2026.07/fs/squashfs/sqfs.c#L814 https://github.com/u-boot/u-boot/commit/561ae28cb56a082cfa90c1c421c4955bc215470b https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc4-integer-overflow-in-squashfs-directory-table-allocation

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 5.2 (MEDIUM).

How severe is CVE-2026-71973? +

CVE-2026-71973 has a CVSS v3.1 score of 5.2 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0019, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-71973? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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