# CVE-2022-50755: linux: In the Linux kernel, the following vulnerability has been resolved:  udf: Avoid double brelse() in udf_rename()  syzb...

CVE-2022-50755 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-50755, released December 24, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2022-50755
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 24, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  udf: Avoid double brelse() in udf_rename()  syzbot reported a warning like below [1]:  VFS: brelse: Trying to free free buffer WARNING: CPU: 2 PID: 7301 at fs/buffer.c:1145 __brelse+0x67/0xa0 ... Call Trace:  <TASK>  invalidate_bh_lru+0x99/0x150  smp_call_function_many_cond+0xe2a/0x10c0  ? generic_remap_file_range_prep+0x50/0x50  ? __brelse+0xa0/0xa0  ? __mutex_lock+0x21c/0x12d0  ? smp_call_on_cpu+0x250/0x250  ? rcu_read_lock_sched_held+0xb/0x60  ? lock_release+0x587/0x810  ? __brelse+0xa0/0xa0  ? generic_remap_file_range_prep+0x50/0x50  on_each_cpu_cond_mask+0x3c/0x80  blkdev_flush_mapping+0x13a/0x2f0  blkdev_put_whole+0xd3/0xf0  blkdev_put+0x222/0x760  deactivate_locked_super+0x96/0x160  deactivate_super+0xda/0x100  cleanup_mnt+0x222/0x3d0  task_work_run+0x149/0x240  ? task_work_cancel+0x30/0x30  do_exit+0xb29/0x2a40  ? reacquire_held_locks+0x4a0/0x4a0  ? do_raw_spin_lock+0x12a/0x2b0  ? mm_update_next_owner+0x7c0/0x7c0  ? rwlock_bug.part.0+0x90/0x90  ? zap_other_threads+0x234/0x2d0  do_group_exit+0xd0/0x2a0  __x64_sys_exit_group+0x3a/0x50  do_syscall_64+0x34/0xb0  entry_SYSCALL_64_after_hwframe+0x63/0xcd  The cause of the issue is that brelse() is called on both ofibh.sbh and ofibh.ebh by udf_find_entry() when it returns NULL.  However, brelse() is called by udf_rename(), too.  So, b_count on buffer_head becomes unbalanced.  This patch fixes the issue by not calling brelse() by udf_rename() when udf_find_entry() returns NULL.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.4-1 | [DEBIAN-CVE-2022-50755](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50755.md) | Dec 24, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.1.4-1 | [DEBIAN-CVE-2022-50755](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50755.md) | Dec 24, 2025 |
| Linux | linux Debian 14 | 6.1.4-1 | [DEBIAN-CVE-2022-50755](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50755.md) | Dec 24, 2025 |

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