# CVE-2021-3656: bpftool: The kernel packages contain the Linux kernel, the core of any Linux operating system.  Security Fix(es):  * kernel: u...

CVE-2021-3656 is fixed in 48 products on 1 platform, first by RHSA-2021:4056, released November 2, 2021. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-3656
- Priority: High
- CVSS: 8.8 (Important)
- EPSS: 0.0066
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 2, 2021

## Description

The kernel packages contain the Linux kernel, the core of any Linux operating system.  Security Fix(es):  * kernel: use-after-free in drivers/infiniband/core/ucma.c ctx use-after-free (CVE-2020-36385)  * kernel: out-of-bounds write due to a heap buffer overflow in __hidinput_change_resolution_multipliers() of hid-input.c (CVE-2021-0512)  * kernel: SVM nested virtualization issue in KVM (VMLOAD/VMSAVE) (CVE-2021-3656)  For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.  Bug Fix(es):  * [HPE 8.3 bug] No EDAC MC0 message with one-DIMM two-processor configuration under RHEL8.3 (BZ#1982182)  * mlx: devlink port function shows all zero hw_addr (BZ#1986837)  * net/sched: act_mirred: allow saving the last chain processed on xmit path (BZ#1992230)  * RHEL8.3 - System hang and / or r/o fs during SVC/v5k/v7k maintenance with ibmvfc (BZ#1993892)  * RHEL8.1 Snapshot3 - PVT:940:virt:4TB:LPM operation failed by returning HSCLA2CF, HSCL365C SRC's - Linux partition suspend timeout (-> documentation/Linux Alert through LTC bug 182549) (BZ#1993952)  * RHEL8.4 - benchTableRepDMLAsyncBarrier regresses by 34% on RHEL8.4 on POWER9 compared to RHEL8.2 (performance) (BZ#1997431)  * [panic] call trace: ice_probe+0x238/0x10f0 [ice] (BZ#1997539)  * [ice, PTP] ice: fix GPIO 1PPS signal  (BZ#1997572)  * Fix locality handling in the tpm_tis driver (BZ#1998219)  * [ice, PTP]: fix Tx queue iteration for Tx timestamp enablement (BZ#2000128)  * PCI passthrough with NVidia GPU "Invalid device 0003:01:00.0 iommu_group file /sys/bus/pci/devices/0003:01:00.0/iommu_group is not a symlink" (BZ#2000602)  * [DELL 8.4 BUG] - System Hangs at Dell Logo When Boot to OS(e1000e with wrong GbE checksum) (BZ#2002335)  * RHEL8.4 - kernel: Fix hanging ioctl caused by wrong msg counter (BZ#2002635)  * kernel: get_timespec64 does not ignore padding in compat syscalls (BZ#2003569)  * [mlx5] eth0: hw csum failure (BZ#2005980)  * xlog_grant_head_wait() does not return and system hangs (BZ#2007413)  * panic while breaking a lease/delegation after user mode helper invocation (BZ#2010331)  * Lockd invalid cast to nlm_lockowner (BZ#2010820)  * [xfstests generic/388] XFS: Assertion failed: 0, file: fs/xfs/xfs_mount.c, line: 1218 (BZ#2011919)  Enhancement(s):  * [Intel 8.5 FEAT] ice: Enable PTP Support (BZ#1998220)  * [Intel 8.5 FEAT] ice: Enable GPIO/SDP Support (BZ#1998221)

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bpftool RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | bpftool ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-abi-stablelists RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-abi-stablelists ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-core RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-core ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-cross-headers ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-debug RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-debug ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-debug-core RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-debug-core ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-debug-devel RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-debug-devel ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-debug-modules RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-debug-modules ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-debug-modules-extra RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-debug-modules-extra ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-devel RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-devel ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-doc RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-doc ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-headers ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-modules RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-modules ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-modules-extra RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-modules-extra ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-rt RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-core RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-debug RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-debug-core RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-debug-devel RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-debug-kvm RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-debug-modules RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-debug-modules-extra RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-devel RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-kvm RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-modules RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-rt-modules-extra RHEL 8 | 0:4.18.0-305.25.1.rt7.97.el8_4 | [RHSA-2021:4088](https://patchblox.com/security/data/fix/linux/rhsa-2021-4088.md) | Nov 2, 2021 |
| Linux | kernel-tools RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-tools ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-tools-libs RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-tools-libs ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-tools-libs-devel RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-tools-libs-devel ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |
| Linux | kernel-uek ol 8 | 0:5.4.17-2136.301.1.2.el8uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | kernel-uek-container ol 8 | 0:5.4.17-2136.301.1.2.el8 | [ELSA-2021-9565](https://patchblox.com/security/data/fix/linux/elsa-2021-9565.md) | Nov 23, 2021 |
| Linux | kernel-uek-container-debug ol 8 | 0:5.4.17-2136.301.1.2.el8 | [ELSA-2021-9565](https://patchblox.com/security/data/fix/linux/elsa-2021-9565.md) | Nov 23, 2021 |
| Linux | kernel-uek-debug ol 8 | 0:5.4.17-2136.301.1.2.el8uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | kernel-uek-debug-devel ol 8 | 0:5.4.17-2136.301.1.2.el8uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | kernel-uek-devel ol 8 | 0:5.4.17-2136.301.1.2.el8uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | kernel-uek-doc ol 8 | 0:5.4.17-2136.301.1.2.el8uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | kernel-uek-tools ol 8 | 0:5.4.17-2136.301.1.2.el7uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | kernel-uek-tools-libs ol 8 | 0:5.4.17-2136.301.1.2.el7uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | kernel-zfcpdump RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-zfcpdump-core RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-zfcpdump-devel RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-zfcpdump-modules RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | kernel-zfcpdump-modules-extra RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | linux Debian 12.15 (bookworm) | 5.14.6-1 | [DEBIAN-CVE-2021-3656](https://patchblox.com/security/data/fix/linux/debian-cve-2021-3656.md) | Mar 4, 2022 |
| Linux | linux Debian 13.5 (trixie) | 5.14.6-1 | [DEBIAN-CVE-2021-3656](https://patchblox.com/security/data/fix/linux/debian-cve-2021-3656.md) | Mar 4, 2022 |
| Linux | linux Debian 14 | 5.14.6-1 | [DEBIAN-CVE-2021-3656](https://patchblox.com/security/data/fix/linux/debian-cve-2021-3656.md) | Mar 4, 2022 |
| Linux | perf RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | perf ol 8 | 0:5.4.17-2136.301.1.2.el7uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | python-perf ol 8 | 0:5.4.17-2136.301.1.2.el7uek | [ELSA-2021-9564](https://patchblox.com/security/data/fix/linux/elsa-2021-9564.md) | Nov 23, 2021 |
| Linux | python3-perf RHEL 8 | 0:4.18.0-305.25.1.el8_4 | [RHSA-2021:4056](https://patchblox.com/security/data/fix/linux/rhsa-2021-4056.md) | Nov 2, 2021 |
| Linux | python3-perf ol 8 | 0:4.18.0-305.25.1.el8_4 | [ELSA-2021-4056](https://patchblox.com/security/data/fix/linux/elsa-2021-4056.md) | Nov 3, 2021 |

---

Data as of 2026-11-08T13:06:02Z 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

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.