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Vulnerability record · CVE-2026-31666 · published 24 April 2026

CVE-2026-31666: Linux kernel vulnerability

Linux · Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() After commit 1618aa3c2e01 ("btrfs: simplify return variables in lookup_extent_data_ref()"), the err and ret variables were merged into a single ret variable. However, when btrfs_next_leaf() returns 0 (success), ret is overwritten from -ENOENT to 0. If the first key in the next leaf does not match (different objectid or type), the function returns 0 instead of -ENOENT, making the caller believe the lookup succeeded when it did not. This can lead to operations on the wrong extent tree item, potentially causing extent tree corruption. Fix this by returning -ENOENT directly when the key does not match, instead of relying on the ret variable.

7.8 CVSS 3.1 High EPSS 0.18% · top 93.8%
7.8CVSS 3.1 base score
0.18%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() After commit 1618aa3c2e01 ("btrfs: simplify return variables in lookup_extent_data_ref()"), the err and ret variables were merged into a single ret variable. However, when btrfs_next_leaf() returns 0 (success), ret is overwritten from -ENOENT to 0. If the first key in the next leaf does not match (different objectid or type), the function returns 0 instead of -ENOENT, making the caller believe the lookup succeeded when it did not. This can lead to operations on the wrong extent tree item, potentially causing extent tree corruption. Fix this by returning -ENOENT directly when the key does not match, instead of relying on the ret variable.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://git.kernel.org/stable/c/316fb1b3169efb081d2db910cbbfef445afa03b9 Patch
https://git.kernel.org/stable/c/4125a194db4a6cf91f619f38788272651cb97dce Patch
https://git.kernel.org/stable/c/450e6a685d0cad95b15f8af152057bd0bf79f50b Patch
https://git.kernel.org/stable/c/ab1e022379c3c811aa72da8eb0c7507859a1d0f5 Patch

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Source: NIST National Vulnerability Database (record CVE-2026-31666), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.