CVE-2026-90259: Linux kernel · btrfs: qgroup: fix a wrong length calculation in qgroup_free_reserved_data()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in e6edde29990af8064b9d12217ec03db231ccd55d : update Linux kernel when convenient.
Data as of 26 Oct 2026, 20:02 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in e6edde29990af8064b9d12217ec03db231ccd55d, c4c136555ff90f1e2921cc42da43daac0ef9985e, 9102b179512e11644fb0489ae62010a09afa199c +2
Exploitation evidence
Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available and has been applied in specific Linux kernel commits. Users and administrators should update affected Linux kernel versions to the fixed versions referenced by the commit hashes to remediate this vulnerability.
Description
A vulnerability in the Linux kernel's btrfs filesystem qgroup subsystem involves incorrect length calculation in the qgroup_free_reserved_data() function. The flaw arises from using a rounded-up end position instead of the correct rounded-up length, leading to an incorrect, larger length value. This has been fixed by introducing local aligned start and length variables to correctly calculate the length.
References
- git.kernel.org/stable/c/202ac9e469b78817512921c5db05cc2140e4ca43 (opens in a new tab)
- git.kernel.org/stable/c/34adc843c28e5cd1f533a1d64f51b0f756fdf945 (opens in a new tab)
- git.kernel.org/stable/c/e6edde29990af8064b9d12217ec03db231ccd55d (opens in a new tab)
- git.kernel.org/stable/c/c4c136555ff90f1e2921cc42da43daac0ef9985e (opens in a new tab)
- git.kernel.org/stable/c/9102b179512e11644fb0489ae62010a09afa199c (opens in a new tab)