Description
The eBPF RINGBUF bpf_ringbuf_reserve() function in the Linux kernel did not check that the allocated size was smaller than the ringbuf size, allowing an attacker to perform out-of-bounds writes within the kernel and therefore, arbitrary code execution. This issue was fixed via commit 4b81ccebaeee ("bpf, ringbuf: Deny reserve of buffers larger than ringbuf") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced via 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") (v5.8-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, v5.8 – < 5.8* | 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 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | kernel-rt +12 | 4.18.0-348.rt7.130.el8 | RHSA-2021:4140 |
| RHEL 8 | perf +26 | 4.18.0-348.el8 | RHSA-2021:4356 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | kernel-tools-libs-devel | 4.18.0-348.el8 | ALSA-2021:4356 |
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 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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_0 | 2-3.1 | SUSE-SU-2021:2198-1 |
| SLE Live Patching 15 SP3 | kernel-livepatch-SLE15-SP3_Update_1 | 1-7.5.1 | SUSE-SU-2021:1977-1 |
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 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | perf +19 | 4.18.0-348.el8 | ELSA-2021-4356 |
Advisories 13
- ALSA-2021:4356 Moderate: kernel security, bug fix, and enhancement update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2021:4356 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Oct 2, 2026
- RHSA-2021:4140 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Aug 14, 2026
- 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-2021:2198-1 Security update for the Linux Kernel (Live Patch 0 for SLE 15 SP3) 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
- openSUSE-SU-2021:1975-1 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-2021:1977-1 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
- ELSA-2021-4356 Moderate: kernel security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 16, 2021
References
- [oss-security] CVE-2021-3489 - Linux kernel eBPF RINGBUF map oversized allocation mailing-list
- https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=4b81ccebaeee885ab1aa1438133f2991e3a2b6ea
- https://www.zerodayinitiative.com/advisories/ZDI-21-590/
- https://ubuntu.com/security/notices/USN-4950-1 vendor-advisory
- https://ubuntu.com/security/notices/USN-4949-1 vendor-advisory
- https://security.netapp.com/advisory/ntap-20210716-0004/