# CVE-2021-47343: linux: In the Linux kernel, the following vulnerability has been resolved:  dm btree remove: assign new_root only when remov...

CVE-2021-47343 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47343, released May 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47343
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 21, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  dm btree remove: assign new_root only when removal succeeds  remove_raw() in dm_btree_remove() may fail due to IO read error (e.g. read the content of origin block fails during shadowing), and the value of shadow_spine::root is uninitialized, but the uninitialized value is still assign to new_root in the end of dm_btree_remove().  For dm-thin, the value of pmd->details_root or pmd->root will become an uninitialized value, so if trying to read details_info tree again out-of-bound memory may occur as showed below:    general protection fault, probably for non-canonical address 0x3fdcb14c8d7520   CPU: 4 PID: 515 Comm: dmsetup Not tainted 5.13.0-rc6   Hardware name: QEMU Standard PC   RIP: 0010:metadata_ll_load_ie+0x14/0x30   Call Trace:    sm_metadata_count_is_more_than_one+0xb9/0xe0    dm_tm_shadow_block+0x52/0x1c0    shadow_step+0x59/0xf0    remove_raw+0xb2/0x170    dm_btree_remove+0xf4/0x1c0    dm_pool_delete_thin_device+0xc3/0x140    pool_message+0x218/0x2b0    target_message+0x251/0x290    ctl_ioctl+0x1c4/0x4d0    dm_ctl_ioctl+0xe/0x20    __x64_sys_ioctl+0x7b/0xb0    do_syscall_64+0x40/0xb0    entry_SYSCALL_64_after_hwframe+0x44/0xae  Fixing it by only assign new_root when removal succeeds

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.14.6-1 | [DEBIAN-CVE-2021-47343](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47343.md) | May 21, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.14.6-1 | [DEBIAN-CVE-2021-47343](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47343.md) | May 21, 2024 |
| Linux | linux Debian 14 | 5.14.6-1 | [DEBIAN-CVE-2021-47343](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47343.md) | May 21, 2024 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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