# CVE-2021-47541: linux: In the Linux kernel, the following vulnerability has been resolved:  net/mlx4_en: Fix an use-after-free bug in mlx4_e...

CVE-2021-47541 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47541, released May 24, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47541
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0030
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 24, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  net/mlx4_en: Fix an use-after-free bug in mlx4_en_try_alloc_resources()  In mlx4_en_try_alloc_resources(), mlx4_en_copy_priv() is called and tmp->tx_cq will be freed on the error path of mlx4_en_copy_priv(). After that mlx4_en_alloc_resources() is called and there is a dereference of &tmp->tx_cq[t][i] in mlx4_en_alloc_resources(), which could lead to a use after free problem on failure of mlx4_en_copy_priv().  Fix this bug by adding a check of mlx4_en_copy_priv()  This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs.  Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug.  Builds with CONFIG_MLX4_EN=m show no new warnings, and our static analyzer no longer warns about this code.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.15-1 | [DEBIAN-CVE-2021-47541](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47541.md) | May 24, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.15-1 | [DEBIAN-CVE-2021-47541](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47541.md) | May 24, 2024 |
| Linux | linux Debian 14 | 5.15.15-1 | [DEBIAN-CVE-2021-47541](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47541.md) | May 24, 2024 |

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