CVE-2026-31666

About vulnerability

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. A flaw was found in the Linux kernel’s btrfs filesystem. An incorrect return value in the lookup_extent_data_ref() function can lead to the system believing a lookup succeeded when it did not. This can cause operations to be performed on the wrong extent tree item, potentially resulting in data corruption within the extent tree.

Live-patch status from KernelCare for each operating system.