Description
The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux kernel | trunk – < v5.13-rc4, linux-5.12.y – < v5.12.4, linux-5.11.y – < v5.11.21, linux-5.10.y – < v5.10.37, v5.7-rc1 – < 5.7* | v5.13-rc4 |
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 | 5.10.38-1 | — |
| Debian 13 | linux | 5.10.38-1 | — |
| Debian 12 | linux | 5.10.38-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | linux-hwe-5.8 | 5.8.0-53.60~20.04.1 | USN-4949-1 |
| Ubuntu 20.04 LTS | linux-oem-5.10 | 5.10.0-1026.27 | USN-4948-1 |
| Ubuntu 20.04 LTS | linux-raspi2 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-riscv-5.8 | 5.8.0-25.27~20.04.1 | — |
| Ubuntu 18.04 LTS | linux-gcp +11 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | kernel-64kb +5 | 5.3.18-59.5.2 | SUSE-SU-2021:1977-1 |
| SLES 15 SP3 | kernel-azure +2 | 5.3.18-38.3.1 | SUSE-SU-2021:1975-1 |
| SLES 15 SP3 | kernel-default-base | 5.3.18-59.5.2.18.2.2 | SUSE-SU-2021:1977-1 |
| SLES 15 SP3 | kernel-syms +1 | 5.3.18-59.5.1 | SUSE-SU-2021:1977-1 |
| SLES 15 SP2 | kernel-azure +1 | 5.3.18-18.50.2 | SUSE-SU-2021:1888-1 |
| SLES 15 SP2 | kernel-default-base | 5.3.18-24.67.3.9.30.2 | SUSE-SU-2021:1890-1 |
| SLES 15 SP2 | kernel-docs +1 | 5.3.18-24.67.3 | SUSE-SU-2021:1890-1 |
| SLES 15 SP2 | kernel-preempt | 5.3.18-24.67.4 | SUSE-SU-2021:1890-1 |
| SLES 15 SP2 | kernel-source +1 | 5.3.18-24.67.2 | SUSE-SU-2021:1890-1 |
| SLES 15 SP2 | kernel-syms | 5.3.18-24.67.1 | SUSE-SU-2021:1890-1 |
| SLES 15 SP2 | kernel-syms-azure | 5.3.18-18.50.1 | SUSE-SU-2021:1888-1 |
| SLES 15 SP1 | kernel-docs +5 | 4.12.14-197.92.1 | SUSE-SU-2021:1912-1 |
| SLES 15 | kernel-docs +6 | 4.12.14-150.75.1 | SUSE-SU-2021:2421-1 |
| SLES 12 SP5 | kernel-azure +2 | 4.12.14-16.59.1 | SUSE-SU-2021:1887-1 |
| SLES 12 SP5 | kernel-docs | 4.12.14-122.74.2 | SUSE-SU-2021:1913-1 |
| SLES 12 SP5 | kernel-syms +3 | 4.12.14-122.74.1 | SUSE-SU-2021:1913-1 |
Show 23 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | kernel-syms +2 | 4.12.14-95.77.1 | SUSE-SU-2021:1891-1 |
| SLES for SAP 15 SP1 | kernel-docs +4 | 4.12.14-197.92.1 | SUSE-SU-2021:1912-1 |
| SLES for SAP 15 | kernel-docs +5 | 4.12.14-150.75.1 | SUSE-SU-2021:2421-1 |
| SLES for SAP 12 SP5 | kernel-azure +2 | 4.12.14-16.59.1 | SUSE-SU-2021:1887-1 |
| SLES for SAP 12 SP5 | kernel-syms +2 | 4.12.14-122.74.1 | SUSE-SU-2021:1913-1 |
| SLES for SAP 12 SP4 | kernel-syms +2 | 4.12.14-95.77.1 | SUSE-SU-2021:1891-1 |
| SLE Real Time 12 SP5 | kernel-rt +3 | 4.12.14-10.46.1 | SUSE-SU-2021:1899-1 |
| SLE Micro 5.0 | kernel-default | 5.3.18-24.67.3 | SUSE-SU-2021:1890-1 |
| SLE Micro 5.0 | kernel-default-base | 5.3.18-24.67.3.9.30.2 | SUSE-SU-2021:1890-1 |
| SLE Micro 5.0 | kernel-rt | 5.3.18-8.13.1 | SUSE-SU-2021:2208-1 |
| SLE Live Patching 15 SP3 | kernel-default | 5.3.18-59.5.2 | SUSE-SU-2021:1977-1 |
| SLE Live Patching 15 SP3 | kernel-livepatch-SLE15-SP3_Update_1 | 1-7.5.1 | SUSE-SU-2021:1977-1 |
| SLE Live Patching 15 SP2 | kernel-default | 5.3.18-24.67.3 | SUSE-SU-2021:1890-1 |
| SLE Live Patching 15 SP2 | kernel-livepatch-SLE15-SP2_Update_14 | 1-5.3.2 | SUSE-SU-2021:1890-1 |
| SLE Live Patching 15 SP1 | kernel-default | 4.12.14-197.92.1 | SUSE-SU-2021:1912-1 |
| SLE Live Patching 15 SP1 | kernel-livepatch-SLE15-SP1_Update_25 | 1-3.3.1 | SUSE-SU-2021:1912-1 |
| SLE Live Patching 15 | kernel-default | 4.12.14-150.75.1 | SUSE-SU-2021:2421-1 |
| SLE Live Patching 15 | kernel-livepatch-SLE15_Update_25 | 1-1.3.1 | SUSE-SU-2021:2421-1 |
| SLE Live Patching 12 SP5 | kernel-default | 4.12.14-122.74.1 | SUSE-SU-2021:1913-1 |
| SLE Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_19 | 1-8.3.1 | SUSE-SU-2021:1913-1 |
| SLE Live Patching 12 SP4 | kernel-default | 4.12.14-95.77.1 | SUSE-SU-2021:1891-1 |
| SLE Live Patching 12 SP4 | kgraft-patch-SLE12-SP4_Update_21 | 1-6.3.1 | SUSE-SU-2021:1891-1 |
| SLE HPC 15 SP1 | kernel-docs +4 | 4.12.14-197.92.1 | SUSE-SU-2021:1912-1 |
| SLE HPC 15 | kernel-docs +5 | 4.12.14-150.75.1 | SUSE-SU-2021:2421-1 |
| SUSE Real Time Module 15 SP3 | kernel-rt +3 | 5.3.18-8.13.1 | SUSE-SU-2021:2208-1 |
| SUSE Real Time Module 15 SP2 | kernel-rt +3 | 5.3.18-39.1 | SUSE-SU-2021:1889-1 |
| SUSE OpenStack Cloud Crowbar 9 | kernel-syms +2 | 4.12.14-95.77.1 | SUSE-SU-2021:1891-1 |
| SUSE OpenStack Cloud 9 | kernel-syms +2 | 4.12.14-95.77.1 | SUSE-SU-2021:1891-1 |
| SUSE Manager Server 4.0 | kernel-docs +5 | 4.12.14-197.92.1 | SUSE-SU-2021:1912-1 |
| SUSE Manager Retail Branch Server 4.0 | kernel-docs +4 | 4.12.14-197.92.1 | SUSE-SU-2021:1912-1 |
| SUSE Manager Proxy 4.0 | kernel-docs +4 | 4.12.14-197.92.1 | SUSE-SU-2021:1912-1 |
| SUSE Enterprise Storage 6 | kernel-docs +4 | 4.12.14-197.92.1 | SUSE-SU-2021:1912-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | kernel-source | 5.14.6-1.4 | openSUSE-SU-2024:13704-1, openSUSE-SU-2024:10728-1 |
| openSUSE Leap 15.3 | kernel-64kb +7 | 5.3.18-59.5.2 | openSUSE-SU-2021:1977-1 |
| openSUSE Leap 15.3 | kernel-azure +2 | 5.3.18-38.3.1 | openSUSE-SU-2021:1975-1 |
| openSUSE Leap 15.3 | kernel-default-base | 5.3.18-59.5.2.18.2.2 | openSUSE-SU-2021:1977-1 |
| openSUSE Leap 15.3 | kernel-syms +2 | 5.3.18-59.5.1 | openSUSE-SU-2021:1977-1 |
| openSUSE Leap 15.2 | kernel-default-base | 5.3.18-lp152.78.1.lp152.8.34.1 | openSUSE-SU-2021:0843-1 |
| openSUSE Leap 15.2 | kernel-docs +8 | 5.3.18-lp152.78.1 | openSUSE-SU-2021:0843-1 |
| openSUSE Leap 15.2 | kernel-rt +3 | 5.3.18-lp152.3.14.1 | openSUSE-SU-2021:0947-1 |
Advisories 20
- USN-4949-1 linux, linux-aws, linux-azure, linux-gcp, linux-hwe-5.8, linux-kvm, linux-oracle, linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- USN-4948-1 linux-oem-5.10 vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- SUSE-SU-2021:1888-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1913-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:13704-1 kernel-devel-longterm-6.6.17-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1912-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1975-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:2421-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1889-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1890-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0843-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1891-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1887-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10728-1 kernel-devel-5.14.6-1.4 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0947-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1977-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1899-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1975-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
- SUSE-SU-2021:1977-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
- SUSE-SU-2021:2208-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
References
- https://ubuntu.com/security/notices/USN-4950-1 vendor-advisory
- https://ubuntu.com/security/notices/USN-4949-1 vendor-advisory
- [oss-security] CVE-2021-3491 - Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass mailing-list
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d1f82808877bb10d3deee7cf3374a4eb3fb582db
- https://www.zerodayinitiative.com/advisories/ZDI-21-589/
- https://security.netapp.com/advisory/ntap-20210716-0004/