# CVE-2021-47342: linux: In the Linux kernel, the following vulnerability has been resolved:  ext4: fix possible UAF when remounting r/o a mmp...

CVE-2021-47342 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47342, released May 21, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47342
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0025
- 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:  ext4: fix possible UAF when remounting r/o a mmp-protected file system  After commit 618f003199c6 ("ext4: fix memory leak in ext4_fill_super"), after the file system is remounted read-only, there is a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to point at freed memory, which the call to ext4_stop_mmpd() can trip over.  Fix this by only allowing kmmpd() to exit when it is stopped via ext4_stop_mmpd().  Bug-Report-Link: <20210629143603.2166962-1-yebin10@huawei.com>

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.14.6-1 | [DEBIAN-CVE-2021-47342](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47342.md) | May 21, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.14.6-1 | [DEBIAN-CVE-2021-47342](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47342.md) | May 21, 2024 |
| Linux | linux Debian 14 | 5.14.6-1 | [DEBIAN-CVE-2021-47342](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47342.md) | May 21, 2024 |

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