CVE Catalog

CVE-2026-74571

Low risk· EPSS 4%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.15%

4th percentile - higher than 4% of all known CVEs

Summary

In the Linux kernel, the btrfs filesystem has a NULL pointer dereference vulnerability when mounting with rescue=ibadroots after corrupting the block group tree or RAID stripe tree root. The function btrfs_update_global_block_rsv() dereferences the missing root based on the feature bit, causing a crash.

Risk Assessment

An attacker with access to a corrupted btrfs filesystem can cause a kernel crash (DoS) by mounting it with rescue=ibadroots, leading to service unavailability.

Recommendation

Apply the Linux kernel patch that skips global block reserve accounting for rescue mounts and exports btrfs_is_full_ro(). Update your system to a kernel version containing this fix.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: btrfs: skip global block reserve accounting for rescue mounts [BUG] Mounting with rescue=ibadroots after corrupting the block group tree root triggers a NULL pointer dereference: BUG: kernel NULL pointer dereference, address: 0000000000000100 RIP: 0010:btrfs_update_global_block_rsv+0x9d/0x1c0 [btrfs] Call Trace: fill_dummy_bgs+0xd4/0x120 [btrfs] open_ctree+0xc6e/0x1ca0 [btrfs] btrfs_get_tree+0x50d/0xa40 [btrfs] The same crash occurs with a corrupted raid stripe tree root, via btrfs_read_block_groups() instead of fill_dummy_bgs(). [CAUSE] With rescue=ibadroots, btrfs_read_roots() allows the mount to continue when either root cannot be read, leaving the corresponding root pointer NULL while its on-disk feature bit remains set. btrfs_update_global_block_rsv() then dereferences the missing root based on the feature bit alone. [FIX] Rescue mounts are fully read-only and cannot start transactions, so the global reserve is never consumed. Under btrfs_is_full_ro(), mark the reserve as full and return before performing the accounting. And since we need to check if the fs is mount fully RO, export fs_is_full_ro() as btrfs_is_full_ro(), and move it to fs.h. [ Squash the fs_is_full_ro() export commit into this one. ]

Vulnerability data from NVD (NIST) · CISA KEV · EPSS