# CVE-2022-50564: linux: In the Linux kernel, the following vulnerability has been resolved:  s390/netiucv: Fix return type of netiucv_tx()  W...

CVE-2022-50564 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-50564, released October 22, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-50564
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0025
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 22, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  s390/netiucv: Fix return type of netiucv_tx()  With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals:    drivers/s390/net/netiucv.c:1854:21: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict]           .ndo_start_xmit         = netiucv_tx,                                     ^~~~~~~~~~  ->ndo_start_xmit() in 'struct net_device_ops' expects a return type of 'netdev_tx_t', not 'int'. Adjust the return type of netiucv_tx() to match the prototype's to resolve the warning and potential CFI failure, should s390 select ARCH_SUPPORTS_CFI_CLANG in the future.  Additionally, while in the area, remove a comment block that is no longer relevant.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.4-1 | [DEBIAN-CVE-2022-50564](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50564.md) | Oct 22, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.1.4-1 | [DEBIAN-CVE-2022-50564](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50564.md) | Oct 22, 2025 |
| Linux | linux Debian 14 | 6.1.4-1 | [DEBIAN-CVE-2022-50564](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50564.md) | Oct 22, 2025 |

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