What’s Vulnerable › Vulnerabilities

CVE-2026-90259: btrfs: qgroup: fix a wrong length calculation in qgroup_free_reserved_data()

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-17 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: qgroup: fix a wrong length calculation in qgroup_free_reserved_data() In that function, we round down the start position and round up the ending position. But during the calculation of @len, we use "round_up(start + len, sectorsize)", which is the rounded up end position, not the rounded up length. Which results a much larger length, and later we are still using "start + len", which is completely incorrect. Fix it by declaring a local @aligned_start and @aligned_len and use them instead.

Affected products

• Linux: 4.13 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/036e6c216be66a085da3a0519f1be5f3230b6e26
• https://git.kernel.org/stable/c/202ac9e469b78817512921c5db05cc2140e4ca43
• https://git.kernel.org/stable/c/34adc843c28e5cd1f533a1d64f51b0f756fdf945
• https://git.kernel.org/stable/c/9102b179512e11644fb0489ae62010a09afa199c
• https://git.kernel.org/stable/c/c4c136555ff90f1e2921cc42da43daac0ef9985e
• https://git.kernel.org/stable/c/e6edde29990af8064b9d12217ec03db231ccd55d

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