# CVE-2021-47479: linux: In the Linux kernel, the following vulnerability has been resolved:  staging: rtl8712: fix use-after-free in rtl8712_...

CVE-2021-47479 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47479, released May 22, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47479
- Priority: High
- CVSS: 7.0 (high)
- EPSS: 0.0023
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 22, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  staging: rtl8712: fix use-after-free in rtl8712_dl_fw  Syzbot reported use-after-free in rtl8712_dl_fw(). The problem was in race condition between r871xu_dev_remove() ->ndo_open() callback.  It's easy to see from crash log, that driver accesses released firmware in ->ndo_open() callback. It may happen, since driver was releasing firmware _before_ unregistering netdev. Fix it by moving unregister_netdev() before cleaning up resources.  Call Trace: ...  rtl871x_open_fw drivers/staging/rtl8712/hal_init.c:83 [inline]  rtl8712_dl_fw+0xd95/0xe10 drivers/staging/rtl8712/hal_init.c:170  rtl8712_hal_init drivers/staging/rtl8712/hal_init.c:330 [inline]  rtl871x_hal_init+0xae/0x180 drivers/staging/rtl8712/hal_init.c:394  netdev_open+0xe6/0x6c0 drivers/staging/rtl8712/os_intfs.c:380  __dev_open+0x2bc/0x4d0 net/core/dev.c:1484  Freed by task 1306: ...  release_firmware+0x1b/0x30 drivers/base/firmware_loader/main.c:1053  r871xu_dev_remove+0xcc/0x2c0 drivers/staging/rtl8712/usb_intf.c:599  usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.3-1 | [DEBIAN-CVE-2021-47479](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47479.md) | May 22, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.3-1 | [DEBIAN-CVE-2021-47479](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47479.md) | May 22, 2024 |
| Linux | linux Debian 14 | 5.15.3-1 | [DEBIAN-CVE-2021-47479](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47479.md) | May 22, 2024 |

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Data as of 2026-11-09T07:25:28Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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