Description
The Linux kernel 4.x (starting from 4.1) and 5.x before 5.0.8 allows Information Exposure (partial kernel address disclosure), leading to a KASLR bypass. Specifically, it is possible to extract the KASLR kernel image offset using the IP ID values the kernel produces for connection-less protocols (e.g., UDP and ICMP). When such traffic is sent to multiple destination IP addresses, it is possible to obtain hash collisions (of indices to the counter array) and thereby obtain the hashing key (via enumeration). This key contains enough bits from a kernel address (of a static variable) so when the key is extracted (via enumeration), the offset of the kernel image is exposed. This attack can be carried out remotely, by the attacker forcing the target device to send UDP or ICMP (or certain other) traffic to attacker-controlled IP addresses. Forcing a server to send UDP traffic is trivial if the server is a DNS server. ICMP traffic is trivial if the server answers ICMP Echo requests (ping). For client targets, if the target visits the attacker's web page, then WebRTC or gQUIC can be used to force UDP traffic to attacker-controlled IP addresses. NOTE: this attack against KASLR became viable in 4.1 because IP ID generation was changed to have a dependency on an address associated with a network namespace.
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 | 4.19.37-1 | — |
| Debian 13 | linux | 4.19.37-1 | — |
| Debian 12 | linux | 4.19.37-1 | — |
| Debian 9 | linux | 4.9.168-1+deb9u5 | DSA-4497-1 |
| Debian 8 | linux | 3.16.70-1 | DLA-1862-1 |
| Debian 8 | linux-4.9 | 4.9.168-1+deb9u5~deb8u1 | DLA-1885-1 |
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 +2 | No fix yet | — |
| Ubuntu 18.04 LTS | linux | 4.15.0-60.67 | USN-4115-1 |
| Ubuntu 18.04 LTS | linux-aws | 4.15.0-1047.49 | USN-4118-1 |
| Ubuntu 18.04 LTS | linux-azure | 5.0.0-1014.14~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-gcp | 4.15.0-1042.45 | — |
| Ubuntu 18.04 LTS | linux-gke-4.15 | 4.15.0-1041.43 | USN-4115-1 |
| Ubuntu 18.04 LTS | linux-hwe | 5.0.0-23.24~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-hwe-edge | 5.0.0-16.17~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-kvm | 4.15.0-1043.43 | USN-4115-1 |
| Ubuntu 18.04 LTS | linux-oem | 4.15.0-1056.65 | — |
| Ubuntu 18.04 LTS | linux-oracle | 4.15.0-1022.25 | USN-4115-1 |
| Ubuntu 18.04 LTS | linux-raspi2 | 4.15.0-1044.47 | USN-4115-1 |
| Ubuntu 18.04 LTS | linux-snapdragon | 4.15.0-1062.69 | — |
| Ubuntu 16.04 LTS | linux | 4.4.0-150.176 | — |
| Ubuntu 16.04 LTS | linux-aws | 4.4.0-1084.94 | — |
| Ubuntu 16.04 LTS | linux-aws-hwe | 4.15.0-1047.49~16.04.1 | USN-4118-1 |
| Ubuntu 16.04 LTS | linux-azure | 4.15.0-1056.61 | USN-4115-1 |
| Ubuntu 16.04 LTS | linux-gcp | 4.15.0-1041.43 | USN-4115-1 |
| Ubuntu 16.04 LTS | linux-hwe | 4.15.0-60.67~16.04.1 | USN-4115-1 |
| Ubuntu 16.04 LTS | linux-kvm | 4.4.0-1047.53 | — |
| Ubuntu 16.04 LTS | linux-oracle | 4.15.0-1022.25~16.04.1 | USN-4115-1 |
| Ubuntu 16.04 LTS | linux-raspi2 | 4.4.0-1110.118 | — |
| Ubuntu 16.04 LTS | linux-snapdragon | 4.4.0-1114.119 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro FIPS 18.04 LTS | linux-aws-fips +2 | No fix yet | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-aws-fips | 4.15.0-2018.18 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-azure-fips | 4.15.0-2006.7 | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | 4.4.0-1011.14 | — |
| Ubuntu Pro 14.04 LTS | linux | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux-aws | 4.4.0-1054.58 | — |
| Ubuntu Pro 14.04 LTS | linux-azure | 4.15.0-1059.64~14.04.1 | — |
| Ubuntu Pro 14.04 LTS | linux-lts-xenial | 4.4.0-164.192~14.04.1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | kernel-rt +12 | 4.18.0-193.rt13.51.el8 | RHSA-2020:1567 |
| RHEL 8 | perf +26 | 4.18.0-193.el8 | RHSA-2020:1769 |
| RHEL 7 | kernel-rt +10 | 3.10.0-1127.rt56.1093.el7 | RHSA-2020:1070 |
| RHEL 7 | perf +18 | 3.10.0-1127.el7 | RHSA-2020:1016 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7.7 EUS | perf +18 | 3.10.0-1062.26.1.el7 | RHSA-2020:2522 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | kernel-azure +2 | 4.12.14-8.13.1 | SUSE-SU-2019:2069-1 |
| SLES 15 SP1 | kernel-docs +5 | 4.12.14-197.10.1 | SUSE-SU-2019:1854-1 |
| SLES 15 | kernel-azure +2 | 4.12.14-5.33.1 | SUSE-SU-2019:1829-1 |
| SLES 15 | kernel-docs +6 | 4.12.14-150.27.1 | SUSE-SU-2019:1855-1 |
| SLES 12 SP4 | kernel-docs +4 | 4.12.14-95.24.1 | SUSE-SU-2019:1851-1 |
| SLES 12 SP3 | kernel-syms +2 | 4.4.180-94.100.1 | SUSE-SU-2019:1852-1 |
| SLES 12 SP3 | kgraft-patch-SLE12-SP3_Update_27 | 1-4.3.1 | SUSE-SU-2019:1852-1 |
| SLES 12 SP2 | kernel-syms +2 | 4.4.121-92.117.1 | SUSE-SU-2019:1823-2, SUSE-SU-2019:1823-1 |
| SLES 12 SP2 | kgraft-patch-SLE12-SP2_Update_31 | 1-3.3.1 | SUSE-SU-2019:1823-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP4 | kernel-syms +2 | 4.12.14-95.24.1 | SUSE-SU-2019:1851-1 |
| SLES for SAP 12 SP3 | kernel-syms +2 | 4.4.180-94.100.1 | SUSE-SU-2019:1852-1 |
| SLES for SAP 12 SP3 | kgraft-patch-SLE12-SP3_Update_27 | 1-4.3.1 | SUSE-SU-2019:1852-1 |
| SLES for SAP 12 SP2 | kernel-syms +2 | 4.4.121-92.117.1 | SUSE-SU-2019:1823-1 |
| SLES for SAP 12 SP2 | kgraft-patch-SLE12-SP2_Update_31 | 1-3.3.1 | SUSE-SU-2019:1823-1 |
| SLE Real Time 12 SP4 | kernel-rt +3 | 4.12.14-8.3.1 | SUSE-SU-2019:2450-1 |
| SLE Live Patching 15 SP1 | kernel-default | 4.12.14-197.10.1 | SUSE-SU-2019:1854-1 |
| SLE Live Patching 15 SP1 | kernel-livepatch-SLE15-SP1_Update_3 | 1-3.3.1 | SUSE-SU-2019:1854-1 |
| SLE Live Patching 15 | kernel-default | 4.12.14-150.27.1 | SUSE-SU-2019:1855-1 |
| SLE Live Patching 15 | kernel-livepatch-SLE15_Update_12 | 1-1.5.1 | SUSE-SU-2019:1855-1 |
| SLE Live Patching 12 SP4 | kgraft-patch-SLE12-SP4_Update_6 | 1-6.5.1 | SUSE-SU-2019:1851-1 |
| SUSE Real Time Module 15 SP1 | kernel-rt +3 | 4.12.14-14.8.1 | SUSE-SU-2019:2430-1 |
| SUSE OpenStack Cloud 8 | kernel-syms +2 | 4.4.180-94.100.1 | SUSE-SU-2019:1852-1 |
| SUSE OpenStack Cloud 8 | kgraft-patch-SLE12-SP3_Update_27 | 1-4.3.1 | SUSE-SU-2019:1852-1 |
| SUSE OpenStack Cloud 7 | kernel-syms +2 | 4.4.121-92.117.1 | SUSE-SU-2019:1823-1 |
| SUSE OpenStack Cloud 7 | kgraft-patch-SLE12-SP2_Update_31 | 1-3.3.1 | SUSE-SU-2019:1823-1 |
| SUSE Enterprise Storage 5 | kernel-syms +2 | 4.4.180-94.100.1 | SUSE-SU-2019:1852-1 |
| SUSE Enterprise Storage 5 | kgraft-patch-SLE12-SP3_Update_27 | 1-4.3.1 | SUSE-SU-2019:1852-1 |
| SUSE Enterprise Storage 4 | kernel-syms +2 | 4.4.121-92.117.1 | SUSE-SU-2019:1823-1 |
| SUSE Enterprise Storage 4 | kgraft-patch-SLE12-SP2_Update_31 | 1-3.3.1 | SUSE-SU-2019:1823-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.1 | kernel-docs +8 | 4.12.14-lp151.28.10.1 | openSUSE-SU-2019:1757-1 |
| openSUSE Leap 15.0 | kernel-docs +8 | 4.12.14-lp150.12.67.1 | openSUSE-SU-2019:1716-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | perf +19 | 4.18.0-193.el8 | ELSA-2020-1769 |
| Oracle Linux 7 | kernel-uek +5 | 4.1.12-124.42.3.el7uek | ELSA-2020-5845, ELSA-2020-5837 |
| Oracle Linux 7 | kernel-uek-tools +3 | 4.14.35-1902.306.2.el7uek | ELSA-2020-5845 |
| Oracle Linux 7 | perf +12 | 3.10.0-1127.el7 | ELSA-2020-5845, ELSA-2020-1016 |
Advisories 26
- USN-4115-1 linux, linux-azure, linux-gcp, linux-gke-4.15, linux-hwe, linux-kvm, linux-oracle, linux-raspi2 vulnerabilities Ubuntu Security Notices (USN) · Sep 7, 2026
- USN-4118-1 linux-aws vulnerabilities Ubuntu Security Notices (USN) · Sep 7, 2026
- RHSA-2020:1769 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Aug 22, 2026
- RHSA-2020:1567 Red Hat Security Advisory: kernel-rt security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Aug 7, 2026
- RHSA-2020:2522 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2020:1070 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2020:1016 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- DSA-4497-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1885-1 linux-4.9 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1862-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2019:1823-2 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:1855-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:1851-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:2450-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:1852-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:1829-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:1757-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:2069-1 Security update for the Linux Kernel for Azure SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:2430-1 Security update for kernel-source-rt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:1823-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:1716-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:1854-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- ELSA-2020-5845 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Sep 11, 2020
- ELSA-2020-5837 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Sep 3, 2020
- ELSA-2020-1769 Important: kernel security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 5, 2020
- ELSA-2020-1016 Moderate: kernel security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 6, 2020
References
- openSUSE-SU-2019:1716 vendor-advisory
- openSUSE-SU-2019:1757 vendor-advisory
- [debian-lts-announce] 20190723 [SECURITY] [DLA 1862-1] linux security update mailing-list
- 20190813 [SECURITY] [DSA 4497-1] linux security update mailing-list
- DSA-4497 vendor-advisory
- [debian-lts-announce] 20190814 [SECURITY] [DLA 1885-1] linux-4.9 security update mailing-list
- USN-4115-1 vendor-advisory
- USN-4118-1 vendor-advisory
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.8
- https://github.com/torvalds/linux/commit/355b98553789b646ed97ad801a619ff898471b92
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=355b98553789b646ed97ad801a619ff898471b92
- https://arxiv.org/pdf/1906.10478.pdf
- https://security.netapp.com/advisory/ntap-20190806-0001/
- https://support.f5.com/csp/article/K32804955
- https://support.f5.com/csp/article/K32804955?utm_source=f5support&%3Butm_medium=RSS