Description
In the Linux kernel before 5.4.2, the io_uring feature leads to requests that inadvertently have UID 0 and full capabilities, aka CID-181e448d8709. This is related to fs/io-wq.c, fs/io_uring.c, and net/socket.c. For example, an attacker can bypass intended restrictions on adding an IPv4 address to the loopback interface. This occurs because IORING_OP_SENDMSG operations, although requested in the context of an unprivileged user, are sometimes performed by a kernel worker thread without considering that context.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 5.3.15-1 | — |
| Debian 13 | linux | 5.3.15-1 | — |
| Debian 12 | linux | 5.3.15-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv +2 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +4 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-azure-5.3 | 5.3.0-1013.14~18.04.1 | USN-4284-1 |
| Ubuntu 18.04 LTS | linux-gcp-5.3 +1 | 5.3.0-1012.13~18.04.1 | USN-4284-1 |
| Ubuntu 18.04 LTS | linux-gcp-edge +2 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-hwe | 5.3.0-40.32~18.04.1 | USN-4284-1 |
| Ubuntu 18.04 LTS | linux-raspi2-5.3 | 5.3.0-1018.20~18.04.1 | USN-4284-1 |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Exploit-DB 1
- Linux 5.3 - Privilege Escalation via io_uring Offload of sendmsg() onto Kernel Thread with Kernel Creds EDB-47779 · local · Dec 16, 2019 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- USN-4284-1 linux, linux-aws, linux-azure, linux-azure-5.3, linux-gcp, linux-gcp-5.3, linux-hwe, linux-kvm, linux-oracle, linux-raspi2, linux-raspi2-5.3 vulnerabilities Ubuntu Security Notices (USN) · Sep 7, 2026
- WID-SEC-2024-1180 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · May 20, 2024
References
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.2
- https://bugs.chromium.org/p/project-zero/issues/detail?id=1975
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=181e448d8709e517c9c7b523fcd209f24eb38ca7
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d69e07793f891524c6bbf1e75b9ae69db4450953
- https://security.netapp.com/advisory/ntap-20200103-0001/
- USN-4284-1 vendor-advisory