CVE-2026-90259
Published Sep 17, 2026
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.
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References
Frequently Asked Questions
What is CVE-2026-90259? +
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.
How do I check if I'm vulnerable to CVE-2026-90259? +
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.