Description
sound/core/timer.c in the Linux kernel through 4.6 does not initialize certain r1 data structures, which allows local users to obtain sensitive information from kernel stack memory via crafted use of the ALSA timer interface, related to the (1) snd_timer_user_ccallback and (2) snd_timer_user_tinterrupt functions.
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 | 4.5.5-1 | — |
| Debian 13 | linux | 4.5.5-1 | — |
| Debian 12 | linux | 4.5.5-1 | — |
| Debian 8 | linux | 3.16.7-ckt25-2+deb8u2 | DSA-3607-1 |
| Debian 7 | linux | 3.2.81-1 | DLA-516-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-riscv +6 | 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-gcp +3 | No fix yet | — |
| Ubuntu 16.04 LTS | linux | 4.4.0-28.47 | USN-3016-1 |
| Ubuntu 16.04 LTS | linux-raspi2 | 4.4.0-1016.22 | USN-3016-2 |
| Ubuntu 16.04 LTS | linux-snapdragon | 4.4.0-1019.22 | USN-3016-3 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | linux | 3.13.0-91.138 | USN-3018-1 |
| Ubuntu 14.04 LTS | linux-lts-utopic | 3.16.0-76.98~14.04.1 | USN-3019-1 |
| Ubuntu 14.04 LTS | linux-lts-vivid | 3.19.0-64.72~14.04.1 | USN-3020-1 |
| Ubuntu 14.04 LTS | linux-lts-wily | 4.2.0-41.48~14.04.1 | USN-3017-3 |
| Ubuntu 14.04 LTS | linux-lts-xenial | 4.4.0-28.47~14.04.1 | USN-3016-4 |
| Ubuntu Pro 20.04 LTS | linux-azure-fde-5.15 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | kernel-rt +10 | 3.10.0-514.rt56.420.el7 | RHSA-2016:2584 |
| RHEL 7 | perf +18 | 3.10.0-514.el7 | RHSA-2016:2574 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | kernel-docs | 3.12.62-60.62.3 | SUSE-SU-2016:2105-1 |
| SLES 12 SP1 | kernel-xen +4 | 3.12.62-60.62.1 | SUSE-SU-2016:2105-1 |
| SLES 12 | kernel-docs | 3.12.60-52.49.3 | SUSE-SU-2016:1690-1 |
| SLES 12 | kernel-ec2 +5 | 3.12.60-52.49.1 | SUSE-SU-2016:2105-1, SUSE-SU-2016:1690-1 |
| SLES 11 SP4 | kernel-docs | 3.0.101-77.2 | SUSE-SU-2016:1672-1 |
| SLES 11 SP4 | kernel-ec2 +7 | 3.0.101-77.1 | SUSE-SU-2016:1672-1 |
| SLES 11 SP3 | kernel-ec2 +7 | 3.0.101-0.47.86.1 | SUSE-SU-2016:2245-1 |
| SLES 11 SP2 | kernel-ec2 +6 | 3.0.101-0.7.53.1 | SUSE-SU-2017:0333-1 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | kernel-xen +3 | 3.12.62-60.62.1 | SUSE-SU-2016:2105-1 |
| SLES for SAP 12 | kernel-xen +3 | 3.12.60-52.49.1 | SUSE-SU-2016:1690-1 |
| SLES for SAP 11 SP4 | kernel-ec2 +7 | 3.0.101-77.1 | SUSE-SU-2016:1672-1 |
| SLE Real Time 12 SP1 | kernel-rt +5 | 3.12.61-60.18.1 | SUSE-SU-2016:1937-1 |
| SLE Real Time 11 SP4 | kernel-rt +3 | 3.0.101.rt130-57.1 | SUSE-SU-2016:1985-1 |
| SLE Live Patching 12 | kgraft-patch-SLE12-SP1_Update_7 | 1-4.2 | SUSE-SU-2016:2105-1 |
| SLE Live Patching 12 | kgraft-patch-SLE12_Update_14 | 1-2.1 | SUSE-SU-2016:1690-1 |
| SUSE OpenStack Cloud 5 | kernel-ec2 +6 | 3.0.101-0.47.86.1 | SUSE-SU-2016:2245-1 |
| SUSE Manager Proxy 2.1 | kernel-ec2 +6 | 3.0.101-0.47.86.1 | SUSE-SU-2016:2245-1 |
| SUSE Manager 2.1 | kernel-ec2 +6 | 3.0.101-0.47.86.1 | SUSE-SU-2016:2245-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | kernel-ec2 +6 | 3.0.101-0.47.86.1 | SUSE-SU-2016:2245-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | kernel-source | 4.8.13-1.1 | openSUSE-SU-2024:10128-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | dtrace-modules-3.8.13-118.14.2.el6uek | 0.4.5-3.el6 | ELSA-2016-3645 |
| Oracle Linux 7 | dtrace-modules-3.8.13-118.14.2.el7uek | 0.4.5-3.el7 | ELSA-2016-3645 |
| Oracle Linux 7 | dtrace-modules-4.1.12-61.1.19.el6uek | 0.5.3-2.el6 | ELSA-2016-3644 |
| Oracle Linux 7 | dtrace-modules-4.1.12-61.1.19.el7uek | 0.5.3-2.el7 | ELSA-2016-3644 |
| Oracle Linux 7 | kernel-uek +5 | 3.8.13-118.14.2.el7uek | ELSA-2016-3645, ELSA-2016-3644 |
| Oracle Linux 7 | perf +11 | 3.10.0-514.el7 | ELSA-2016-2574 |
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.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- Linux Kernel 4.4 (Ubuntu 16.04) - 'snd_timer_user_ccallback()' Kernel Pointer Leak EDB-46529 · dos · Mar 11, 2019
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 24
- RHSA-2016:2584 Red Hat Security Advisory: kernel-rt security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2016:2574 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- USN-3016-1 linux vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-3018-1 linux vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-516-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3607-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-3017-3 linux-lts-wily vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3019-1 linux-lts-utopic vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3020-1 linux-lts-vivid vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3016-2 linux-raspi2 vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3016-3 linux-snapdragon vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3016-4 linux-lts-xenial vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- SUSE-SU-2016:1937-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1672-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10128-1 kernel-debug-4.8.13-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:0333-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2105-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1985-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1690-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
- SUSE-SU-2016:2245-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
- WID-SEC-2024-0147 Linux Kernel: Schwachstelle ermöglicht Offenlegung von Informationen BSI CERT-Bund (WID) · Jan 17, 2024
- ELSA-2016-3644 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 20, 2016
- ELSA-2016-3645 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 20, 2016
- ELSA-2016-2574 Important: kernel security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 9, 2016
References
- SUSE-SU-2016:1690 vendor-advisory
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e4ec8cc8039a7063e24204299b462bd1383184a5
- USN-3017-1 vendor-advisory
- 46529 exploit
- SUSE-SU-2016:1985 vendor-advisory
- USN-3017-3 vendor-advisory
- openSUSE-SU-2016:2184 vendor-advisory
- USN-3018-2 vendor-advisory
- https://github.com/torvalds/linux/commit/e4ec8cc8039a7063e24204299b462bd1383184a5
- USN-3021-2 vendor-advisory
- USN-3017-2 vendor-advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1335215
- RHSA-2016:2584 vendor-advisory
- RHSA-2016:2574 vendor-advisory
- USN-3019-1 vendor-advisory
- openSUSE-SU-2016:1641 vendor-advisory
- DSA-3607 vendor-advisory
- 90535 vdb-entry
- USN-3016-2 vendor-advisory
- USN-3016-1 vendor-advisory
- SUSE-SU-2016:1672 vendor-advisory
- USN-3021-1 vendor-advisory
- USN-3018-1 vendor-advisory
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9a47e9cff994f37f7f0dbd9ae23740d0f64f9fe6
- [oss-security] 20160511 Re: CVE Request: alsa: kernel information leak vulnerability in Linux sound/core/timer mailing-list
- SUSE-SU-2016:2105 vendor-advisory
- USN-3016-3 vendor-advisory
- https://github.com/torvalds/linux/commit/9a47e9cff994f37f7f0dbd9ae23740d0f64f9fe6
- USN-3016-4 vendor-advisory
- USN-3020-1 vendor-advisory
- SUSE-SU-2016:1937 vendor-advisory